I wouldn't worry about the clearance of your cooler in the case, but more in relation to the RAM on your motherboard. You'll definitely want to put your RAM In BEFORE the cooler. That said, you need to check the clearance. The cooler will allow for 1.5" of RAM clearance.
What kind of PC you're building all depends on how much you want to spend and what you're using it for...so it's an impossible question to answer, as it is. You can also take a better look at the power supply thing. Power requirements, again, depend on your needs. That said, I recommend Ultra power supplies or you can go with a Corsair. Regardless, I wouldn't go cheap on a power supply (think more like $60-$100). They go bad faster than you think and a good power supply can save you from having to replace other parts in your machine due to a power spike from a storm. I would also recommend a modular power supply (where you only use the power cables you need, and no more). This allows for more room for air flow in your case and room to work with.