I was finally able to free myself of the Taris memory leak bug, last night. It's pretty much a showstopper, and while it's a very high priority bug for the devs, if you get caught in it, CS will not help you out. So if you go to Taris, here are some suggestions to minimize it's effects.
1. Put the "Emergency Fleet Pass" ability on your hotbar and don't use it. This is your "get out of Taris bug for free" card.
2. If you start to get an unusual amount of lag when crossing zones, opening your map, or going into buildings, you are probably going to get hit by this bug soon. You can avoid it by untracking all your quests and unchecking your map options before entering buildings (especially the starport and crater base).
3. If you are unfortunate enough to get hit by the bug and your framerate permanently drops to 0.5 or so, shut the game down and start it back up. Use your "Emergency Fleet Pass" ability and you should be free. If not, restart and get back to the character select screen. In settings, disable sound, drop the resolution to 800x600, and use the lowest graphics settings. Shut down any programs you have running in the background. Now select the character and get back into the game. Hit the 'L' button. Move the mouse over one of the lighted mission buttons and wait for it to get brighter. Click on it once, and wait until the light goes out. Repeat until all the missions are untracked. Restart, and you should be fine. After this, avoid Taris until they fix the problem.
It was only really bad for me until I finish my class quest on taris, so I just took off at 35 or so, wish I could have stick around for rest of the quest.