Yes, the 3500+ is a great CPU right now. You may feel that the 3000+ or 3200+ offers better value though, depending on whether you need the extra power provided by the 3500+ or not.
Yes, you can upgrade it, to an FX or X2 in fact, so you definitely have no issues there.
amd opetron? they cheap and oc like a monkey covered in butter sliding down a slide :O if ya into ocing but the 3500+ is a very nice cpu it pretty much the one before u start getting really $$$$ next one up from that is like anutha 200 bucks in australia :O
well 3500+ is really a bargain, 3700 is quite a bit expensive with double L2 cache which in AMD's case is not really that important. then there is the 3800+ which is so much more expensive (i have this one, haha). opterons are a good idea if you want to OC.
to AOD is the 3700 really that much more expensive? its not even that bad here in South Africa.
cool, so what do u have to do to overclock the CPU? I know that you have to get a program for that and you might have to increase the voltage but thats really all i know.