Good news from the TF2 Official Blog: another class pack is on the way.
According to the blog, the Sniper is next in line for Achievements, and the accompanying update will be the largest yet. Players can expect more tweaks and new maps in addition to the Sniper-oriented content. No specific date was mentioned.
For those who have the Xbox 360 version, Valve assures gamers they are still working on the console update:
If you're wondering what's taking so long, since the content is "done" on the PC already, it's mostly been around fitting it all onto the XBox. The original version of TF2 in the Orange Box was very close to the XBox's memory limit, and all the additional TF2 content we've produced has pushed well beyond it. We've found a couple of nifty ways to get back a bunch of that memory, but it's turned out to be a lot of work, and that's what most of our time is being spent on. In the meantime, we're going to get a code update out to address the server cheating that's going on.