I forgot about that article Cameron. I agree, it's a good one (I always have to read em a couple times to get that stuff to sink in)..

If you're interested in learning how to pick out a relay that is 1) sufficient to meet your needs and 2) within your budget, you might want to peruse this Tyco electronics catalog and compare it to the Bosch catalog as well:

http://www.tycoelectronics.com/industry/appliance/pdf/catalogs/1308242_10-Automotive_Relays.pdf

http://www.boschmotorsandcontrols.co.uk/relais/relais.pdf

The VF4 series Potter & Brumfield relays are probably OK for what you're trying to do and at ~$2 a piece, compared to ~$10 a piece (plus shipping) for the Bosch relays (as advertised at the Aardvark store and others), this may be a better choice since you can probably pick them up at your local automotive parts store (Pep Boys, Checker, Autozone, etc)?

Maybe look for this p/n to start:
VF4 45F11


Actually, I checked Mouser Electronics online, and it looks like this relay is about $7.25 if you only bought one:
http://www.sourceesb.com/DistributorDetails.asp?regid=0&sname=Manufacturer&type=W&search=Potter+%26+Brumfield%2FTyco+Electronics&filter=None&titleid=36952&companyid=104333&distid=14938&pgnum=1&pgpos=48&action=DIST_NAME_CLICK

ebay:
This looks like a pretty good deal for $20 if you need wiring, connectors & a relay to hook up some lights:
http://cgi.ebay.com/ebaymotors/Universal-Fog-Lamps-Lights-WIRING-HARNESS-KIT-w-Switch_W0QQcmdZViewItemQQcategoryZ33709QQihZ018QQitemZ280071742328QQtcZphoto#ebayphotohosting

...and if you're planning on going nuts, like Cameron, get yourself a set of 10 relays for a good price! (I noticed these don't have brackets, but you could glue some on with Loctite):
http://cgi.ebay.com/ebaymotors/Lot-of-10-Hella-Relays-12V-30-amp-SPDT-w-Diode-Boxed_W0QQcmdZViewItemQQcategoryZ40019QQihZ018QQitemZ280072754340QQtcZphoto