I prefer Waves RCompresors - then TRacks Opto Compresor

Lastly ProChannel.  It's always been my opinion that Prochanel doesnt handle heavy lifting well.  I'll use it as long as it doesnt require the needle to move much

As far as Dongles slowing down DAW's...I have not experienced that. 

Prochannel also for me.

a) Prochannel + PC2A

ProChannel +1

UAD 1176 / LA2A and / or Prochannel  76 and / or 2A.    UAD sounds superior to me, especially the 1176 but tehy are all very useful!  I think Cakewalk compressors rival Waves emulations but can't touch UAD

1# UAD Neve 33609, UA 1176, UA LA-2A
2# Pro Channel's comps
3# T-Racks Black/White/Red-Opto

If those don't cut the mustard I still have the UAD Neve channel strip and the Waves SSL's strips as well. (Rarely does this happen)

But my UA card is usually doing tape emulation duty, so the prochannel comps get used quite a bit.

PC on my PC 

Pro-channel 

DBX160XT (hardware compressor) on vocal/bass recording, and then a) prochannel compressor.

Pro-channel comps most often, something on the rare times none of them will do the job in hand, something else. Though these days it's usually pro-channel. The one thing I could do with is an emulation of the Alesis 3630. Sure, it's cheap, but it's also distinctive. Which is what makes it useful. How about some emulations of cheap-but-common hardware as well as the high-end stuff Cakewalk? As for Pro Channel and cpu usage, I usually have stuff running there in every track all the time. The cpu hit is minimal.