I'm hoping to do some drivetrain maintanence for the first time over the weekend. I have a shimano 1/2 x 3/32" chain and a 10 sp cassette to replace. Seems pretty straightforward, but I do have a question about the chain tool I need. I have a standard chain tool (one that comes in the Topeak kits). The instructions that came with the chain recommended a few specific Shimano chain tools (a tl-cn32, cn23, or cn27). Do I need to buy another chain tool or will the one I have work fine?

No worries, generic ones work fine. Got me a cheapo Nashbar one and have put on many chains with no problems.

I've found the Topeak chain-tool on my Alien II to be surprisingly good. Tight & true. For shop use, though, I use a Park CT-3. But the Topeak one will get you through no problem.

If you're going to be breaking chains all the time (working in a shop) then a good one is worth it. If not, the cheap ones function just fine even if they aren't a pleasure to use.