Awesome! Sounds very similar to my rig - all I'd need to do to mine is change the processor to a quad core (I have a fast, but dual-core, Phenom II 550), a bigger HD, and an extra two gigs of ram, and it'd be like an exact copy of yours.
It is indeed pretty amazing what you can do on a budget. Also happy to hear Rise of Flight runs well on your system - I've been hesitant to get it because I wasn't sure how my PC would deal with it, but sounds like it should do fine.
Have fun with it
