I am currently running Vista on a computer with about 250 GB max capacity hard drive (I have 127 GB of free space left) and 2 GB of ram on a Dell Inspiron 530. I mainly use the computer for games, but would like to branch out a bit. I don't want to remove Vista, solely because I know it will play more games at the moment than Linux. However, I do want to try my hand Linux for all of my other tasks. Do I have enough space left on my current drive to partition and run Linux without any real decrease in performance for either Vista or Linux? In asking this, I am assuming no and am looking at buying another hard drive to run Linux on specifically. I have never had more than one hard drive installed on one computer, and would like to be sure that I can have them both, with different OS's on each, and just restart my computer whenever I want to switch between playing games and performing other tasks. As a last part of this question, are there any external hard drives that could run on my computer at the same speed as an internal drive? Please excuse my relative technological illiteracy about hardware ;).

Right, yes you have plenty of space (a typical install can be anywhere from 4GB up, depending on what you install). Yes, you can have several drives in one system without a problem (I had 4 in my old machine, 2 in my current one), but you will need to go into the BIOS to set which one to boot from. Almost all distro's will pickup the windows install and add an entry to the boot menu so you can select it easily. Finally, no, you wont find a drive which has similar performance to an internal drive - SATA has a speed of several GB/s (SATA being the current internal drive connector), whereas USB has a limit of just 480MB/s. Penguin

Actually, current Linux boot loaders should install and let you boot from the second drive for Linux and the first for Windows. You may have to manually edit the grub.conf file to do this so it presents the Windows option on your bootup screen.