It will fit, just for future reference, if you're on newegg, you can go to the product you're looking for, in this situation a case, and go down to where it says "Motherboard Compatibility" and it will say which size it is compatable with.
This is the order of ATX (BTX) sizes (from smallest to largest)
- Flex ATX
- Micro ATX
That fan is an 80mm, and you should get another case. Spend the extra money on the case, trust me, its worth it.
Nothing against ATi, but, their chipsets aren't that good. Other than the crossfire ones of course.
I think you should drop the 754 idea, and go w/ 939, although Socket AM2 is about to be released, their processors won't be under $300, the difference between the 754 3000+ and the 939 3200+ is $40, and you can find a 939 Mobo for about the same price.