Sorry that I haven't provided any thoughts yet, I've been busy lately. Hungover Sunday is great time to do this, though
Something very general first. Overall, I've been very happy with the change. Windows 7 is really a good OS. Sure OS X is better in some cases, but so is Windows in some.
After switching the PSU for the Antec, it's been totally quiet. I also connected the CPU fan to a case fan connector so the default rpm is a bit lower (thanks for the tip!). I also bought two extra fans to improve the airflow, but only one is in use at the moment because putting a fan in the upper fan holders will cause quite a lot noise from what I have heard. They were only a tenner each so I don't mind.
IIRC some of you were asking how the dual display setup works. I have to say it's brilliant. It has increased my efficiency a lot because I can now easily have two windows next to each other, or four if I squeeze them in. I can easily have dozens of windows open when I get excited about something, and I'm lazy to close them because I might not find it again (history and bookmarks exist, I know, but come on I'm lazy

).
In gaming, the dual displays help too. I only game on the other one but being able to have things like Facebook, email, IM and hardware monitor open at the same time are huge benefits. I can immediately see e.g. a FB message without exiting the game. If it's something important, I can exit and reply. If it isn't, I'll continue gunning down some terrorists
I've been very pleased with the overall performance, too. Pretty much all games run at the highest graphics. BF3, in particular, looks absolutely astonishing. I haven't even done any OCing, so I can squeeze out some extra frames in the future if needed. 8GB of RAM also helps a lot and I can live my window-full life without worrying about performance loss.
As for the SSD, I've found that 64GB is enough for sure. Right now, I have 19.6GB of free space in it. Windows install takes a lot more space than OS X, so I only had like 30GB left after installing Windows. All my files are stored in the 1TB Samsung, and the 2TB works as a backup. I just need to remember to change the install to F drive instead of C when installing games, otherwise it's very simple.
Some of you were inquiring about the backup software. I first tried something called Cobian Backup, but didn't like it. I decided to give Windows' own backup software a try. So far, it has worked for me. It's integrated into Windows anyway so I believe it should be decent.
All in all, I have no regrets. I knew what I was getting, and I got what I wanted. I still love my MBA, and iPhone, but I think Apple can't offer me a desktop suitable for my needs.
One question. Does anyone have any recommendations on a remote controller? I liked the fact that I could control my iMac from my bed using the Apple Remote, but I haven't found anything similar for PCs. I don't mind if I need to get a Bluetooth or IR receiver, but something for Windows Media Center would be nice.
Also, if you have any questions, feel free to ask. I'm more than happy to try answering it.