iArmBands ArmBand / Arm Band for Google Nexus One, HTC Incredible, & HTC T-Mobile G1 Android gPhones / google phone
I have a few different armbands I'll use for different occasions, but this is probably the all-around best-fit for the G1.  Touchscreen still works reasonably well through plastic, and it's a comfortable enough fit with proper hole placement for headset/peripherals.     Downsides are that it's not the *perfect* fit, and depending on the connector/adapter you use for your headphones, it may become dislodged by the elastic retention material.  This has not been a major issue for me, but has happened once or t