OK, since Christmas is coming up I decited that I was gonna ask for nothing besides upgrades for my computer. That includes a new motherboard/CPU (pentium 2 350MHz), video card, and hard drive. Now I was wondering if I need to but a fan of some sort to cool my PC down. The problem is I plan to keep my PC on most of the day and I need to know what kind of PC cooling thingy i need to buy
Install all your hardware in a Full Size Tower not a mini or mid. Manufactures love it when we use mini and mids everything runs hotter and breaks down sooner. Some full size towers even have an extra mount on the back so an extra pelletier fan can be installed fo r exhaust. I always leave my tower lid backed off one inch for extra air flow.
Full tower cases are bloody huge and frankly, for an ordinary computer you simply don't need one. A mid-tower case is PLENTY (minis are good for transportation but they're very cramped - I would not overclock a computer that was in a mini-tower case). All you need to do to ensure a long life for your components is that all cables are tied up neatly and out of the way of the airflow (use nylon ties - they don't break like rubber bands and can be easily cut off later). If you still feel that heat is a problem, try and imagine the airflow and remove 1 or 2 expansion slot covers to provide good through-flow. As long as you have air circulating through your case you'll do fine.
In fact, a full-tower case without good circulation is worse than a mid tower case with good circulation. Maybe if you're planning to send a celeron 333 to 500, you'll want a full tower case so you can put 5 case fans in, but it's simply too impractical for the general user, full towers are impossible to lug around!