Also on a related note I was speaking to another dev who told me that he always puts position:relative to all elements in the CSS Reset. Is this good practice?
Internet Explorer has a bug when the body is made position: relative, so I'd not do it myself. However, someone may have put it in a reset in order to combat other bugs (this may be why your dev does this), but I would say it's not a good idea.
If you use something like Chrome's Inspect, Opera's Dragonfly or Firefox' Firebug, you can see the amount of space an element is taking up with margins vs positioning (margins can be highlighted which I find useful since I can't otherwise make margins visible).
The elements are kind of like house shingles, except they overlap the other way (from bottom of the page to top). Ew, like petting a snake backwards!