Safari using 6GB of RAM?

I'm not sure if this belongs in the applications or the OS forum, but my apologies if it's in the wrong place.

I'm running 10.6.6 on a 27" iMac. I have no plug-ins other than AdBlocker installed on Safari, and all of my software is up to date. I've noticed my machine running a little sluggish the last day or so, and activity monitor shows that Safari (with just one tab) is using almost 6GB of RAM. When I open it, it starts out around 300MB and within a minute or two my activity monitor shows almost 6B of Real Mem used.

Things I've tried:

- Cleared the history cache
- Disable accelerated composting
- Disable back/foward cache
- Disable AdBlocker
- Cleaned everything out with Onyx, including all cookies, logs, cache, etc

Basically Safari open at all is killing every other app that I run on my system. Google Chrome, for comparison, uses around 30MB of RAM with one tab open.

I've been Googling like a maniac, but everything I find points to cache, and I'm not really sure what else to try.

Thanks in advance.

Bah, murphy's law - as soon as you post something, you find the answer.

I had AdBlocker disabled, but the Plugin file still existed in /Library/Application Support/SIMBL/Plugins.

Deleting it entirely and relaunching Safari seemed to do the trick, in case anyone else finds this via Google or so.