I've got Windows 7 on my Mac too. It a good operating system, much better than XP (but of not as good, as OSX of course!)
8 gigs is plenty, but if someone is happy to pay for you to go to 16 gigs, go for it!
However, watch out for the damn Shockwave Flash plug in. It has a memory leak in it, and if you have a lot of ram, it will eat it if you are running a browser (like Safari or Firefox). Therefore it's wise to get the "Click to Flash" plugin installed to halt Flash in its tracks. π
I'm pleased your office colleagues had a good experience. I had a very similar experience too. They thought the computer was a hard drive!!! π There was complete disbelief when I had it up and running!
Tom