No.
The 3GS is still fine, but the 3G is effectively obsolete as of now. It's MUCH slower than the 3GS so I can only imagine how much slower than the 4th-phone it'll be.
Add to that all the other improvements (camera, screen, etc.) and it seems like an easy choice to me. (The screen alone is reason enough. Even though it's fast enough, my wife is upgrading from her 3GS JUST because of the screen!)
iPad? There's no way I'll be buying a 1st gen. It'll clearly be getting a better screen, more RAM, and probably a front-camera next year. I'm betting the 1st-to-2nd gen jump of the iPad will be just as great as the 1st-to-2nd gen jump that happened to the iPhone in 2008.
Apple loves to do big jumps from 1-to-2 but then a smaller jump from 2-to-3. It worked well for me on the iPhone to buy a 2nd gen, I'll be doing the same with the iPad.