I'm not sure if this has been mentioned yet but don't buy your 4GB of ram from Apple. You can get it for roughly 1/2 the cost from any reputable vendor and it's INSANELY easy to install.
Otherwise, enjoy. I bought my first Mac in Oct 2007, bought my fiancee one for Christmas that year, then my best friend got a Macbook Pro, my father and brother now have iMac's as well.
I love mine, it's trouble free and more importantly
worry free. After 15 years of building my own PC's, I'll never go back. The OS is simple, elegant, virus and spyware free 100% of the time.
This is coming from someone who has been in IT straight out of College. I used to despise them, now... not so much.
Also, I'd check into MacMall. With their rebates on the Mac ($100), Parallels Virtualization software ($70) and a free printer ($80), tax free to boot you come out about 400 dollars 'ahead'. This makes up for the refurb pricing. Parallels allows you to run Windows or Linux in tandem with OS X, as opposed to one or the other (as bootcamp does).. however bootcamp can be very valuable too if you chose to work in Windows only for specific tasks.