Seriously...are you THAT important that you need to do both at once?
Well I would grudgingly admit that it would be nice on some occasions. I can recall a couple of instances... One time when a client called me and needed a file which I happened to have on my BB. It would have been nice if I could have simply put him on speakerphone, fired it off in an email, informed him I sent it, then have him confirm he received it and it was indeed what he needed. There have been other calls where somebody was giving me an address to meet them, and it would have been convenient if I could have gone to speakerphone, put the address as they fed it to me into google-maps, view the traffic layer, and give an eta on my arrival.
Granted doing both is not all important... but it would be nice to complete some tasks while on a call in lieu of having to tell the person on the other end "I'll get back to you on that" or "I'll take care of it after we finish this call."
I dont mean to burst your bubbles but really it makes very little difference whether you use 3G or EDGE to surf, with that kind of browser it makes little difference. Just my opinion.