If that is SERIOUSLY all you're going to use it for, buy a cheap one. You can pick them up for a couple of hundred quid now.
And...when Jaime comes along later and disagrees and says I am talking bowlocks, dont listen to him, he knows nowt 
I agree, I bought my first "own" computer for £1300 back in april 2000 and looking back on it's "stats" its a big pile of crap, and a slow pile of crap at that!!
i didnt really need a new computer but for about £550 i got a decent one built to my requirement from
www.pcspecialist.co.uk, i opted out of getting a floppy drive and got a 23-in-1 card reader since i have phones and cameras using all kinds of different cards (early card readers werent XD compatible) it has a fast enough processer to be able to run my internet as well as watching DVDs and stuff or listening to music, I dont play games on it, and i got a big handful of office software included
by buying a build-your-own, you can opt out of the crap you dont want, ie i got a new mouse and keyboard and a flat panel LCD monitor but chose not to have a modem installed, no speakers as my own are top end, and no printer or scanner as i found preferred ones cheaper than their options
and even now you can still get quite a bit more for less than what I paid, as more and more PC packages and offers come out, they can be out of date within 6 months!