If you aren't overclocking then you can get whatever RAM you want and won't see much difference. Yes, lower numbers are better for RAM timings, but it doesn't make much of a difference. Maybe a frame or 2 more with low latency stuff. As long as it has a CAS Latency of 2 or 2.5 you're good.
If you aren't overclocking then you definitely don't need PC3700. Just get a good set of PC3200 with lower timings but still at a decent price. You add Corsair back onto your list since you aren't OCing.
http://www.newegg.com/Product/Product.a ... 6820146883
http://www.newegg.com/Product/Product.a ... 6820145449
Those are pretty much the same RAM from both Corsair or OCZ. Get which ever your prefer or is cheaper.