well, if you're on win xp, nod32 is pretty sweet, vista.
started off with nod32 as i had it on XP, randomly kills the internet for no apparent reason, it shouldn't, only 32bit internet, and no real fix except uninstalling, lots of people have had the issue. mcaffee, says it supports vista, get trial, first bit goes ok, says what do you want to download and install on trial, downloads it, then it goes to install it, boom, "your version of windows is not currently supported, installation exiting........." , so mcaffee sucks. avast, fine until it despite being told to let all cs:s ports, lotro introduces massive lag, turn off automatic virus scanning, lag goes, but altogether useless. kapersky, used to be a nice properly user friendly, but its turned into the "new user friendly" version, ie lots of big pretty buttons, lots of very advanced sounding things, and all the useful options moved around, hidden and more difficult to customise which made me not like it.
trend pc, vista compatible, firstly you install , it has a firewall, BY DEFAULT IE 32 and 64, and firefox have all outgoing requests allowed, thats a good start, all incoming data for those apps is BY DEFAULT denied. useless piece of retarded kit, so finally fixed that and got internet back, then i got some slowdown in lotro, turned off active scanning and firewall and lag goes, then 20 mins later, while it shouldn't be actively scanning i get a BSOD, which was down to the trend .exe, which when searched on internet is just basically crap for vista.
latest suggestion for something that works in vista is f-secure, so guess i'll try that today. but the current state of vista AV support is shocking.