Thanks all for the suggestions. I've found one that I like, the ZoneAlarm one fits my needs best. We don't really have a porn problem in my household and there are no children. I'm the most web-savvy person by far in my home and I am home all day. If I wanted to spy I could, but this is just to protect us from stuff we don't want to see, not for me to spy on anyone in particular.
A lot of it can come up when you're not looking for it, and then those images stay in your mind. I don't even like the stuff, find it to be a turnoff, but it can have a strong effect, just one picture. In lieu of getting rid of the internet altogether, my family decided to try this solution. All of us agreed to pitch in to cover the cost of the program. I wanted to find something that was powerful, intelligent (blocking what should be blocked and not what shouldn't) but unobstrusive, and ZoneAlarm fit the bill. I already had the firewall and loved it.
Thanks for everything.
For those that may come along afterward, I'll add my two bits. I can very strongly recommend Dansguardian to those running Linux distributions. It's a free, powerful content filter which will allow you to control access to what gets onto your system - either software/malware-wise or inappropriate web material. It actually filters on the content of individual web pages. While it's default configuration is pretty restrictive, it's easy to administer in order to tailor it to what you deem appropriate.