 PVID 1 is the default, but if you change that on an interface, page 52 ftp://ftp.dell.com/Manuals/all-products/esuprt_ser_stor_net/esuprt_powerconnect/powerconnect-2708_User%27s%20Guide_en-us.pdf then it will use the PVID you set for untagged traffic. So if you put LAG3 in PVID 139, untagged traffic will go to 139 and tagged will go to VLAN 10. If the Cisco is dropping untagged into 139 with a PVID of 139 then everything should work fine with your configuration and do what you want it to do. 
I have a convoluted image which will be crazy to look at but I'm hoping I can explain it sufficiently: I currently have a single Powerconnect 2716 connected two Poweredge 2950's running as ESXi Hypervisors, and their datastores are on an MD3000i iSCSI SAN (the main use of the switch is the iSCSI san, the servers have backup connections for the client/guest network access). [IMAGE] The hypervisors vmnic config was hokey at best because we didn't have the second gigabit switch to have enough ports to run everything and have redundancy so I ended up using a bunch of 10/100 ports on my Catalyst 3750 PoE switch for Guest machines and my iSCSI traffic on the 2716.   I now have the second 2716 and going through the configs on the old switch I realized I had taken my iSCSI ports, and Guest machine network ports in it out of vlan1 by using pvid's. Here's my dilemna I want to trunk traffic between the two switches for several vlans, but not others. My proposed solution is [IMAGE] (4) vlans 1, 10, 130, 139. (3) LAGs: 1 (ports 2-4), 2 (ports 7,8) 3 (ports 14,14) vlan membership will be: [IMAGE] [IMAGE] [IMAGE]   -VLAN1 is for the switch management, I'm going to have my switches addressed as 192.168.1.1 and 192.168.1.2 and I want to trunk VLAN1 across LAG1 so I can manage both switches and either: plug in to either switch on port 1 with a laptop, or use a remote VM guest with the VLAN trunked in on LAG2 -VLAN10 is for my vMotion, just a 10.x.x.x and I'd planned to pipe it on the same LAG as my guest machine traffic -VLAN130 is my iSCSI SAN -VLAN139 is my Client/Guest Machine/vSphere access What I'm afraid of is traffic from VLAN139 with ingress filtering off and untagged egress on port 16 that might traverse the trunk on LAG 1 (ports 2,3,4) (via VLAN1) and causing a loop since the 2716 doesn't support STP. [IMAGE] I want to trunk the iSCSI, Switch Management, and vMotion across the two Dell switches but I want the Guest machines to go up their switches respective uplinks. I can't have any loops otherwise all my client/server traffic will traverse across one Dell to the other Dell to find the working uplink when the cisco STP auto disables one of the ports Can I do this, even though by default all ports are in VLAN1 untagged? Or am I going to have to redesign this and use PVID's to separate ports 10-16 and put my VLAN10 on LAG2 along with the iSCSI traffic? Can VLAN 10 exist on PVID 2 while the Trunk between the 2716's is in PVID 1 and still pass the traffic between the switches? Have I fried everyone's brain with my images and my 'just enough to be dangerous' knowledge? Thanks in advance! :)
Confused on what I should be doing as far as VLAN vs PVID