Essential security/utility software

Hi,

My new system will be arriving shortly and although this question is a little
on the generic side I'm sure some will have suggestions that I hadn't thought
of. Basically, I'm polling to see which softwares people use to secure the
ship and keep it running smoothly. So far, it seems that the following are
necessaries:

Anti-Virus - seems like Norton's Corporate Edition does the job without
bloating things up

Firewall - not sure which is best here (I'll be subscribing to a cable modem
service through Adelphia) although I would rather take time to learn how to
set up a complex yet effective firewall than a simple one that leaves you
overly vunerable or overly restricted.

Norton Utilities - people seem to say it is good for tuning a system,
especially the defrager, but all the added thingies negate the good it does.

Pop-up Stopper and Ad-killer - lots of varieties. I guess the trick is to find
the ones that do the job yet don't plant their own scripts/bots.

If you can add/subtract from this list please feel free and if you have a
favorite hunting ground (online or offline - I'm in southern California) for
this type of software I'd be glad to hear about it.

Thanks very much.