I'm shopping for a Treo 600 headset.

1) If I got a headphones 2.5 - 3.5 adapter: Can I use the headphones to hear my telephone call & use the Treo's built in mic top talk during a call? This would let me use my really nice earbuds.
Otherwise I guess I'll have to get a (speaker & mic combo) headset.

2) How would an audio snob rate these headphone/mic combos on the market? Is a $40 Seido the equivalent audio quality of $10 Sony headphones?

3) Would the Seidio Audio Adapter (Standard 2.5mm Jack to Nokia 2.5mm Jack) let me use the nice Plantronics headset I used with my old nokia & my Treo 180 with my Treo 600? http://www.seidioonline.com/ProductD...=ADA%2D25MN25F

Thanks.