Trying to decide between USB headsets

[ExoticFish]

so after my finding out the hard way that Apple did not include pre-amped line-in on their powerbooks (why Apple why?!?) i've been looking into USB headsets. At first i was looking at Logitech but after reading reviews of the 200 and 300 i was far from impressed. so now i'm looking at either of these:

Sennheiser PC155
Sennheiser PC135

Plantronics DSP-500
Plantronics DSP-400

I'm thinking that i would probably go with the smaller of each brand (PC135 or DSP-400) The reviews of both have been great (the Sennheiser a little better) but i love the fact the the Plantronics DSP-400 fold up so they would be easy to carry since i'd use them with my PowerBook as well as my PC.

Anyone have any suggestions? Any other suggestions in headsets i should be looking at?

 

[wordmunger]

I have the plantonics DSP-100 USB headset. Have been mightily disappointed. Sound quality of the mic is not as good as the iBook's internal microphone. It also has a big node-thingy on the cord, which makes it not as portable as it looks. Don't know about the others you've cited, though.