Thanks a lot for the comments and advice geofelt.
I ended up with the MB, CPU and 8gb Ram listed above, but using the stock cooler for now. It is noisy so will look into replacing it but not a priority atm.
I also ended up buying a 128gb SSD for my OS as you suggested, and although that decision resulted in a few problems initially, I'm very happy with the speed.
I ran into a mix of problems during this upgrade which others might use/learn from when they need to upgrade:
First I switched out the MB/CPU/RAM and hooked up my original HDD with Win7. This resulted in endless BSOD and I never actually got Win7 started up. This is a common problem when changing MB/CPU, and the best (only) solution is really a clean install of win.
I still had stuff on my OS disk I wanted to keep so decided against a format+install on that, and bought a SSD disk instead.
After some research I went for the OCZ Vertex 3 120gb. Unplugged all other drives (important when installing OS on SSD), plugged in the SSD and powered up. The disk showed up in bios, where I checked the settings were correct and rebooted. During the Win7 install it couldn't find the disk.. I rebooted and went into the BIOS which now couldn't see the disk either.
I tried everything, but after a little research/googling it was clear that a lot of ppl had similar problems with the OCZ drives.. I RMA'ed it and got a Samsung SSD 830 128gb instead. (The tech ppl in the shop tested it while I was there and confirmed it was "a bad disk" - took 5min to get a new one
The Samsung works without a problem, and Im up and running on my new and greatly improved PC.
I did have some problems mounting both of the 2.5" SSD in my Antec P182 though. The problem with Antec 182 and others is that the screws just doesn't match with the mounting bracket/case (too long/short, big/small). I came up with a custom solution though.
The OCZ Vertex 3 I attached to the included mounting bracket with screws, and attached that to the case with some double sided tape.
For the Samsung 830 I tried something different. I had bought a mounting bracket in the shop, and again attached the disk to this with screws. I emptied my old toolbox and found 1 screw that I was able to use for attaching case/bracket. To secure it in place I used some cable binders, and the end result is actually not bad
I uploaded a few pics of both methods:
Double sided tape on the OCZ Vertex 3:
Using cable binders with the Samsung 830: