The technologically inept, such as myself, are afraid to abandon that which they're used to and content with. Will the move from I.E. to Firefox be something that takes time to get used to? What exactly are the advantages? It doesn't seem like a "browser" has much to it; what's the big deal, really, and could the move pose any potential complications?
Well there are several answers to your question. You seem to be coming at this from a practical pov but I will nevertheless offer some idealogical basis first.
Microsoft agreed to a standards-compliant internet where future upgrades to things like style sheets (what makes texts look different colors, sizing, placing text boxes, etc) but then did their thing their own way, causing us designers to have to make two sets of designs (and before anyone says we should just design for the majority, that's impossible because oftentimes IE simply doesn't work at all!)
Secondly, I am anti Microsoft anyway.
As for practically, I think Firefox is neater, slightly faster, has tabbed browsing (IE7 will have them but it is not widely available yet and has security holes), and has more upgrade options (you can get plugins to customize it in rather cool ways and everything is free).
Perhaps for you it would not be that big of a deal but everyone I know who has tried it has stuck with it. It's free and a small download; you can try it out without stopping using IE.
If you don't feel you need to upgrade that's fine, but I have a vested interest in plugging Firefox because if everyone used it, Robert and my web design and coding skills would be better spent; now we have to constantly guess how things will go (like all those bugs you keep getting) because IE never implements things right the first time. Realistically, not everyone is going to use it, but we sure wish they would
You can read up about the features of Firefox before deciding to download on their website, to see if you like it.