Using old hardware to make a torrent box.

I build a small wiring closet in an empty closet in my house with my modem and router. I plan to also put a small machine to download torrents for me to.

The specs will most likely be crap I have in my basement:
Pentium III ~450Mhz and matching ASUS motherboard. Probably very little RAM, assume a single stick of 128mb. Generic video card, not even sure if it will be AGP. I'm probably going to have to buy a small harddrive around 20-40Gb. The machine won't have much cooling since it'll need to be quiet.

The features I'd like are webserver and torrent client+web interface. I want the most lightweight OS and software.

What are you suggestings?

>>15
I tried Gentoo once and couldn't figure it out. I'm not a programmer and I haven't the slightest idea what each of the CFLAGS do.
They make your system cooler; think Freezer's transformations. -Ox is the level of transformation, 3 is the slick final one, and the rest are to cheer him up.

>>16
Did I read correctly when it said there was a menu based installer that let you setup stuff and it will compile automatically?
It's no fun if you don't do it by hand.

VROOM VROOOM!