I upgraded from 8spd to 10spd and went with Ultegra shifters and an XTR RD. The Ultegra shifters have a single click of inward trim on the big ring and fine clicks of outward trim on all three positions.

I am still using the 8spd 105 triple FD and Shimano square taper crankset, but my FD shifting is still improved over the same FD with the 8spd shifters.

The rear shifting is perfect. I am using teflon coated cables for both derailleurs now.

Check your hub to make sure it can take an 11 tooth lockring before buying an 11-xx cassette, not all 8spd hubs will take an 11 because the lock ring will bottom out before the cogs are tight. All should be able to take a 12.

I'm using a Wipperman chain with the connex link. I don't ever put chains together with pins on any of my bikes. The chain tool is only used to shorten new chains to the correct length.

Also, if you have V brakes, you will need to get a "travel agent" to compensate for the difference in brake lever pull ratios.