Well, I've tried Norton up to 2 versions before the current one, it was ok more or less. I've tried Mcafee up to the current version, after the recent patches, it has gotten much better, although, like Norton, it draws too much memory. I had tried ZoneAlarm Internet Security up to a version before the current (the current had too many incompatibilies, I couldn't even install it). It seemed a bit picky and had its share of problems. If you can get it to work, it's very good though. There's also Trend Micro Internet Security and F-secure, but I haven't tried any of those recently.
Nod is very good, I've tried it up to the current version, it always delivers and it's extra light on the system. If you want just an antivirus and are willing to pay, get Nod. If you want something free, AVG Free is considered very good, although I've only recently installed it on one of my PCs, so I can't tell you much about it.
For firewalls, if you want something free, Sunbelt-Kerio Free version or Comodo are good but they can be a pain to configure (especially Comodo - lots of popups). If you want a commercial one, I'd take Outpost (which is a bit tricky to configure if you're not into a bit of technical stuff), or you could try the various Internet Security packages.
Anyway, if you want it easy, most IS packages has one month trial, there are at least 4-5 good ones to consider, so start the trials, see if they work well with your system, visit their support forums, and pick the one you like (although by the time you finish going through all the trials, if everything goes well, the new versions will come out
). Anyway, if you're going to go with the packages, it's best to try them all and see what works better with your PC. Otherwise, my personal preference is NOD and one of the mentioned standalone firewalls.
I'm currently using Mcafee Total Protection. It's getting better thanks to the patches, I'm currently not having much of a problem besides some minor quirks.
And just for the record, it's good installing a dedicated anti-spyware program. If you want something free, I'd suggest SpyBot-Search and Destroy, otherwise, get Spysweeper.