How Vital to surf as Non-Admin./Standard User?

Hey all,

I'm familiar with the "How to Protect Yourself from Malware" sticky over in the malware Forum, but aside from all of the GREAT info. there, does anyone know of (or is anyone willing/able to provide) a list (of sorts) containing (in order) the most important security measures one can take to protect their computer when online? Obviously the top few are well-known and fairly obvious (I think?) - A Good Quality Firewall and Anti-Malware program (not sure which would come first between Antivirus and Anti-spy programs or if they are considered "equally" important), don't go to suspect or sketchy sites such as porn, etc., be careful what is typed into the address bar, use strong passwords, use site-checking tools such as WOT or McAfee's Site Advisor - but after those few, it seems to get a bit foggy (for me it does anyway).

Specifically I am wondering about how important it is to NOT surf the web as an admin (not access the web/net from an admin account)? I have been practicing this for years now (and have advised others to follow this course), but I find it causing problems with my mothers computer (running XP), as far as programs properly updating, etc. (she is almost completely tech-illiterate ... worse than me if you can image that!).

I think I could set hers up so that certain programs would update (or could be manually updated) from her non-admin (standard-user) account, but I have always had trouble understanding the whole "Permissions" and "Task Scheduling" things. Perhaps a SIMPLE tutorial on those would help me.