Need second opinion

[Bob The Mercenary]

Recently finished the first PC I've ever built and I just wanted to make sure I didn't make any blunders in the process. Here are the specs:

AMD Phenom 2 X4 975 3.6GHz
Nvidia GeForce GTX 550ti
40GB SSD for the OS
1TB 7200rpm for storage
MSI 870A-G54 motherboard
4GB of RAM to start, might upgrade to 8
Blu-Ray writer

My big question is the fan configuration. I went budget on the case, it's a mid-ATX by PowerSpec. It came with one intake fan on the lower front side, one rear exhaust, and two spots on the left side for additional fans. There I added a 120mm and 80mm set to intake because I've heard any side fans should be intakes and not exhausts. Any case modding to the lid is pretty much out of the question because there is just no space between the PSU and blu-ray for a fan.

I also added a hard drive blower that exhausts air out the front and upwards. I tried a PCI fan for some extra exhaust, but it was interfering with the air flow through the graphics card so I removed it. I'm just wondering if there is anything I could do better to increase cooling. Right now the CPU stays between 28.5C and 30C when idle, about 35-40C when Oregon Trail is running. I hit it with Prime95 and got it to 65C before I stopped it because I heard the max temp for my particular CPU is 60C.

I'm definitely going to swap out the stock heat sink, but I can't decide between one of those dual 120mm performance heat sinks or liquid cooling. I'm leaning towards the fans because I like the idea of air over the entire chipset.

Another question is, did I select the best components for my money? My limit was $200 on the CPU and $250 on the graphics card. I've heard a lot of "meh" reviews of both, though there are youtube videos of the 550ti running Crysis 2 like a champ.

Also, I'd like to break into overclocking by revving my processor up a bit, but how much is recommended? I'd really like to go for 4GHz, but not sure if there would be enough difference in performance to bother.