The symptom I observed was that my real memory used crept up over 1GB after a couple of hours of usage. My T42 only has 1GB of RAM so that's bad. I could see this by firing up Windows Task Manager and looking at the Commit Charge at the bottom right. The Mem Usage of iexplore.exe would be a couple of hundred MB. When I'd stop IE7 the Commit Charge would drop lots more than what was attributed to iexplore.exe. Something was leaking somewhere! I suspect Javascript.
I thought I'd try Firefox again, again. Wanting to get as current as possible, I downloaded Firefox 3.5 beta 4. I haven't had a bit of trouble from the beta.
Most of the Add-ons I'd used before are still valid with Firefox 3.5 beta 4. Only Tab Clicking Options wouldn't work with it. This was easily replaced with Close Tab by Double Click. You don't even have to set any options. On QuickDrag I also checked "Open tabs for text searches in the foreground."
Besides the previous tweaks, I also found one to make search results open in a new tab.
howtogeek.com says:
Type about:config into the address bar, and then put the following into the filter box:This time, I also turned off third party cookies.
browser.search.openintab
Double-click the value to change it to true.
So far, so good.