am not sure if you will find some thing in that price range, and when you say large number how large you are talking about here 50 hits or 5000 hits per day.
else than that you will need lots bandwidht too. so what i will advice you here if your site new then you will need some time for the site to get known so start with some celaron box with 512 MB in let say managed.com and keep an eye on the box, you will get to know if you need to add one more server due to bandwidth or that box will be enough for you.
talking about 5000 files each about 4 MB size then we are talking about 20 GB of space, well managed.com will offer you 80 GB hard drive mostly 50 will be usable.
and that will be a celaron box 80 GB hard drive 1000 GB of transfer with cpanel will be around $900 a year and if you want the p4 2.4 with 120 Gb hard drive 1000 GB bandwidht then you are talking about $1260 a year.