Ask yourself this - does the iPhone 4 meet your needs? It does mine so I went and brought it last night after waiting a while for the white one. Love it and defo improvement from 3G and 3GS !
3G owner here and planning on upgrading Monday. I assume there will be an upgrade next summer, but predict the timing will go something like . . .
June announcement
July-Aug out of stock
Sept: Some annoying flaw discovered
Oct: In stock without waiting
So, why not. I am tired of how slow apps open on my 3G compared to the 4.
I upgraded to the 4 from a 3GS this week. Its a HUGE difference. The camera is phenomenal, display is amazing, gyroscope for gaming is awesome. It was totally worth it and i'm glad i didn't wait.