If you can afford to wait until June when the AM2 and competing CPUs are released by all means wait.
If you do not wish to wait the 3200+ is still a good deal although an AMD64 dual core is even better if you can afford it.
You can certainly opt for a 3200+ now and upgrade to a Dual Core socket 939 later when the new CPUs are released which will drive prices lower barring any unforeseen problems.