bsear, Be careful, the Ultegra/600 shifters you are looking at are for a double not a triple. They won't work well with your crankset. The RSX 8 speed will work. You will gain the advantage of the paddle, but these are lower end compared to the Ultegra shifters.
Considering the amount of money the 8 speed shifters will cost, have you looked at a set of 9 speed/triple 105 brifters? I know it will take a new chain and a new cassette, so it will cost a little more, but it will be a huge improvement over what you have now and should be a lot cheaper than a 10 speed set up. I went the route of first upgrading from 7 triple to 8 triple with an Ultegra (r) and RSX (L) combo then went to 105 9 speed triple. All of this was used. I actually passed on upgrading to 10 speed because I like the 9 speed 105 so much. Just a thought.