user400: 
If you believe in Shakyamuni Buddha the answer is No, because Buddha
  was clear about the previous Buddha Kassapa and the next Buddha
  Maytreia

If that's the case, then buddha must be very few in numbers. Why so many want to be a buddha and reach nirvana if only very few would win the lotery?
I've heard that there are many buddhas. Sidartha is buddha sankyamuni. That there are many buddha that are simply less famous.
If that's the case, is there any living buddha in the world now?

user533: It will vary according from school to school, in Theravada tradition there are 6 Buddhas, 4 before Shakyamuni Buddha, Himself and Maytrea (Next Buddha). This is what Buddha saw when he contemplate this world and past lifes while meditating. 
In Tibetan Buddhism they talk about 35 Buddhas, Chinese Buddhism will probably give you a different number and so on, but answering strictly from a Suttas' perspective I believe 6 is the answer, at least that is what Shakyamuni was able to see we cannot know if Maytrea will look into the future and see more Buddhas.
Bear in mind I am talking about full enlighted Buddhas that teach the Dhamma, not private Buddhas, most of Buddhas are private Buddhas and they can go on unnoticed by regular people.

user295: In one Buddha Sasana period there can be only one Buddha. Buddhas are indeed few if you look at the gap between Buddhas. But time into the past is infinite hence there are infinite number of Buddhas. Our Buddha got definite prophecy from 28 Buddhas Dipankara Buddha. 

user5676: There are many people that are technically buddhas in this world right now (having removed the four veils, as described in "the luminous mind: the way of the buddha" by Kalu Rinpoche), however, according to the buddhist traditions, there are "founder" buddhas only from time to time. Each "founder" buddha guides many beings to buddhahood, that in turn will guide many beings to buddhahood. By many I don't mean millions, but I guess, without proof, that there are several thousand buddhas right now in this world.

user157: According to the Mahayana text the Lotus Sutra, the number of Buddhas are innumerable. In fact a significant proportion of the text is spent emphasising just how many Buddhas (and Bodhisattvas) there are and just how many world systems they cover.
This is just from the introduction

and the nun Yasodharâ, the mother of Râhula, along with her train;
  (further) with eighty thousand Bodhisattvas, all unable to slide back,
  endowed with the spells of supreme, perfect enlightenment, firmly
  standing in wisdom; who moved onward the never deviating wheel of the
  law; who had propitiated many hundred thousands of Buddhas; who under
  many hundred thousands of Buddhas had planted the roots of goodness,
  had been intimate with many hundred thousands of Buddhas, were in body
  and mind fully penetrated with the feeling of charity

The text goes on for another twenty eight chapters drilling that message home. 
NOTE - even though it is highly repetitive I love this text. If you want a flavour of the cosmic vastness of Mahayana Buddhism then I recommend. It's a mind blowing read.

user503: There had been infinite number of Buddhas before and there will be many more.
In this Kalpa, We already have four Buddhas and there will be one more Buddha. That's why this Kalpa is called Bhadda-kappa.
Extracted it from here.

In the current kalpa, it is said we are fortunate to have experienced
  five Buddhas. Kusanda Buddha, Konagamana Buddha, Kasyapsa Buddha and
  Buddha Shakyamuni. The Buddha of the future is called Maitreya Buddha.

Read more about Bhadda-kappa from here. At Page 12 

400: <blockquote>
  <p>If you believe in Shakyamuni Buddha the answer is No, because Buddha
  was clear about the previous Buddha Kassapa and the next Buddha
  Maytreia</p>
</blockquote>

<p>If that's the case, then buddha must be very few in numbers. Why so many want to be a buddha and reach nirvana if only very few would win the lotery?</p>

<p>I've heard that there are many buddhas. Sidartha is buddha sankyamuni. That there are many buddha that are simply less famous.</p>

<p>If that's the case, is there any living buddha in the world now?</p>
 533: <p>It will vary according from school to school, in Theravada tradition there are 6 Buddhas, 4 before Shakyamuni Buddha, Himself and Maytrea (Next Buddha). This is what Buddha saw when he contemplate this world and past lifes while meditating. </p>

<p>In Tibetan Buddhism they talk about 35 Buddhas, Chinese Buddhism will probably give you a different number and so on, but answering strictly from a Suttas' perspective I believe 6 is the answer, at least that is what Shakyamuni was able to see we cannot know if Maytrea will look into the future and see more Buddhas.</p>

<p>Bear in mind I am talking about full enlighted Buddhas that teach the Dhamma, not private Buddhas, most of Buddhas are private Buddhas and they can go on unnoticed by regular people.</p>
 295: <p>In one Buddha Sasana period there can be only one Buddha. Buddhas are indeed few if you look at the gap between Buddhas. But time into the past is infinite hence there are infinite number of Buddhas. Our Buddha got definite prophecy from <a href="http://en.wikipedia.org/wiki/List_of_the_twenty-eight_Buddhas" rel="nofollow">28 Buddhas</a> <a href="http://en.wikipedia.org/wiki/D%C4%ABpankara_Buddha" rel="nofollow">Dipankara Buddha</a>. </p>
 5676: <p>There are many people that are technically buddhas in this world right now (having removed the four veils, as described in "the luminous mind: the way of the buddha" by Kalu Rinpoche), however, according to the buddhist traditions, there are "founder" buddhas only from time to time. Each "founder" buddha guides many beings to buddhahood, that in turn will guide many beings to buddhahood. By many I don't mean millions, but I guess, without proof, that there are several thousand buddhas right now in this world.</p>
 157: <p>According to the Mahayana text the Lotus Sutra, the number of Buddhas are innumerable. In fact a significant proportion of the text is spent emphasising just how many Buddhas (and Bodhisattvas) there are and just how many world systems they cover.</p>

<p>This is just from the introduction</p>

<blockquote>
  <p>and the nun Yasodharâ, the mother of Râhula, along with her train;
  (further) with eighty thousand Bodhisattvas, all unable to slide back,
  endowed with the spells of supreme, perfect enlightenment, firmly
  standing in wisdom; who moved onward the never deviating wheel of the
  law; who had propitiated many hundred thousands of Buddhas; who under
  many hundred thousands of Buddhas had planted the roots of goodness,
  had been intimate with many hundred thousands of Buddhas, were in body
  and mind fully penetrated with the feeling of charity</p>
</blockquote>

<p>The text goes on for another twenty eight chapters drilling that message home. </p>

<p>NOTE - even though it is highly repetitive I love this text. If you want a flavour of the cosmic vastness of Mahayana Buddhism then I recommend. It's a mind blowing read.</p>
 503: <p>There had been infinite number of Buddhas before and there will be many more.</p>

<p>In this <a href="http://en.wikipedia.org/wiki/Kalpa_(aeon)">Kalpa</a>, We already have four Buddhas and there will be one more Buddha. That's why this Kalpa is called Bhadda-kappa.</p>

<p>Extracted it from <a href="http://buddhists.org/history-of-buddhism/kalpas-in-the-buddhist-religion/">here</a>.</p>

<blockquote>
  <p>In the current kalpa, it is said we are fortunate to have experienced
  five Buddhas. Kusanda Buddha, Konagamana Buddha, Kasyapsa Buddha and
  Buddha Shakyamuni. The Buddha of the future is called Maitreya Buddha.</p>
</blockquote>

<p>Read more about Bhadda-kappa from <a href="http://dhammadownload.com/File-Library/MinGunSayadawGyi/MinGunSayadawGyi-TGC-V1P1.pdf">here</a>. At Page 12 </p>
