Hello.
Well, as I'm sure you know: The RAM is the most important upgrade on the list. Making the move from 2GB of RAM to 4GB of RAM was amazing; I can't even imagine what it will be like for you. Everything will run so much smoother, you can do more at once, etc. you will definitely be pleased with that upgrade.
The SSD (I'm not very up-to-date with SSDs, I don't know which models are good etc.) but any SSD is an improvement upon any hard drive. You'll notice a huge boost in desktop speed/responsiveness, and boot time should be hugely decreased. However, as has been said, RAID 0 with some fast hard drives isn't a bad option either. Whatever you decide to do with your storage devices will yield big gains in speed, that's for sure.
Windows 7 is an amazing OS. I love it. Coming from Vista 64 Bit, it was a great upgrade. Everything feels smoother, snappier, etc. and it's also more practical to use, and is generally easier to use, you won't be disappointed.
The Noctua fans there are fairly good, but they're slightly overpriced, and you can get fans with better static pressure for the money, but they won't be as quiet. If you must have silence, then get them; they won't disappoint there, and I'm sure they'll be an upgrade over your current fans. If your budget/ears will allow you to, I'd personally pick up a 120mm x 38mm fan instead, they generally have higher static pressure than 25mm fans, and generate this at a lower dB rate. Soemthing like the Sunon Denki from
www.scan.co.uk would be good - mine is very quiet and gives me great temperatures.
I've not had any personal experiences with your mouse, but from the reviews, it seems to be good. Personally, I'd just get a Logitech MX518 just because it's tried and tested, and cheaper than the CoolerMaster mouse. It also has Logitech's amazing warranty, meaning that if your mouse ever breaks, you can phone them, and have a replacement mouse within a couple of days.