Look, if you asked about the 3500+ or the 3800+, then I'm sure it's not straining your budget to get a 3700+ when it is middle ground.
Overclocking is never a guarantee, so the people who are telling him to get a low-end CPU and then overclock it are giving him false guarantees that a 3000+/3200+ will hit 2.5/2.6/2.7 easily.
The 3700+ has the specs 2200 Clock Speed/1024 KB or 1MB Cache/2000 HTT. The 3800+ has the specs 2400/512k Cache/2000 HTT. Apparently, the 1MB cache is more valuable than that 200 extra clock speed boost.
The 3700+ is better than a 3800+. If the 3700+ runs at 2.4 GHz through overclocking which I do not guarantee, then it will outperform the 3800+ and do slightly bettter than the 4000+.
The 3700+ should be your choice of processor.