Google Talk is BAD
For some reason, Gmail doesn't like it. A friend of mine had his Gmail account LOCKED OUT when he installed it. Google, of course, doesn't respond (other than auto response emails with no information) to his pleas to turn back on his gmail.
So, again, DO NOT INSTALL GOOGLE TALK and you should think long and hard about depending on Gmail, considering how they promptly shut off his email and won't turn it on for 24 hours (or so they say... he's still offline 14 hours later).