purchasing new cpu4overclocking need help!

hello i am new to this all and i thought this would be a good spot to post a thread. i do have some knowledge of overclocking which is not that much but im planning on purchasing a new cpu and motherboard in my local frys ad they had 3 cpu and motherboard combos that i was interested in and i was wondering if you guys could help me.

the first one i see is a intel core 2 duo processor E6600 with a ECS P4M900T-M motherboard. for $229

2nd is a intel core 2 duo processor E6600 and a asusu P5N-E 650i SLI motherboard for $325

and 3rd is a intel core 2 duo E4300 and abit IB9 pro motherboard for $169


well first of all i read and saw that the E6600 is a great processor so i was considering that. but the motherboards i read some reviews on both and read that the 2nd combo motherboard is very good for overclocking with a great cpu. yet i read for 3rd combo that the processor is great for overclocking and the motherboard isn't that bad. i would be doing alot of gaming not much apps or anything. my question is basically will there be much difference in the 3rd and 2nd combo because i want a pretty gaming rig but i dont have 1000 dollars laying around. would be a better investment in getting combo 2 with the e6600 or combo 3 with the e4300.

sorry if i dont have all the info or anything i am a noob and any help with my future computer would be more than greatly appreciated thanks again!!