How well do HL2 and CS S run for you? Do you launch Steam and then the game?
Half-Life 2 plays fine under CrossOver, you'd think it's a native OS X game... kinda spooky sometimes. Very nifty. While I loaded Counter-Strike: Source, I didn't really play it much, but it appears to run fine too. Based on
screenshots off their compatibility forum, seems like it's pretty much a supported CrossOver app.
You install Steam using the CrossOver install wizard, which then downloads the latest Steam from Valve directly and pre-configures a "bottle" automagically. You then run Steam using the Steam icon in the CrossOver apps folder (right from OS X, CrossOver will launch if it's not running), and install Half-Life 2 or whatever Steam game you're going to run. I run HL2 by just clicking the Half-Life 2 icon in my CrossOver apps folder, for a while I had it on my dock too.
Icons for Windows apps that would normally pop onto the Start menu are replicated in your CrossOver Apps folder, in case that wasn't clear. There's also a drop-down available within CrossOver that lists them all in one place like the Start Menu normally would.
CrossOver Mac really is pretty amazing for the stuff that works under it, and like VMware and Parallels, I think there's a free trial so you can give it a shot with your apps so you don't have to buy it if it doesn't work for you.
I don't want to paint the picture that it's the best Windows-on-Mac gaming platform though, Boot Camp will still run pretty much everything since you're running real Windows, while CrossOver is a Windows API translation layer that was reverse-engineered with primary development focus on Microsoft Office/Quicken/Steam.
Codeweavers actively supports the following games according to their
Compability Forums: Call of Duty, Call of Duty 2, Counter-Strike, Counter-Strike: Source, Day of Defeat, Day of Defeat: Source, EVE Online, Half-Life, Half-Life 2, Half-Life 2: Episode 1, Prey, Team Fortress 2, Team Fortess Classic, The Orange Box, World of Warcraft. Others might work, might not, and when they do, with varying degrees of success.
Check out those forums if you want to know how a certain app works for others under CrossOver, and for any "tweaking" that might be needed like DirectX settings or other Windows voodoo that only makes you appreciate OS X that much more.
