I would wait if I was you but if you can't wait only get the 3GS. Getting the 3G would be a huge waste of money and you will be frustrated when it docent support all the new features in iPhone OS 4.0.
OK, here's the $64,000 question -- I've decided to upgrade to an iPhone as I've once again been in a situation where it would have been nice to access my e-mail while conducting errands. Chatted with a co-worker yesterday who has the 3GS-16 but said the 3GS-32 would be better; however, the 4G is rumored to be coming out in June. So, would it matter if I went ahead and got an iPhone (definitely a 3GS and not a 3G) or should I wait until the 4 comes out to see how much prices drop?
I am already an AT&T customer with a Nokia phone. AT&T will upgrade me to the 3GS-16 for $199 plus 2-year commitment; the 3GS-32 for $299 plus 2-year commitment; or the 3G-8 for $99. I am currently leaning toward the 3GS-16 and wonder if prices will drop dramatically when the 4 is released. It's about a two month wait, so I'm thinking to tough it out and see. Thoughts?