http://irradiatedsoftware.com/sizeup/
It's not a tiling WM, but augments the standard OS X window management keyboard shortcuts with grid stuff, and doesn't have any odd side effects with GUI apps.
Personally I think OS X and its app population comfortably swing the overall usability balance vs desktop Linux so I won't follow your footsteps :-)
Being able to have windows automatically be positioned is key to the tiling wm, I feel. It allows you to have a layout work as you'd expect without fumbling or thinking about it.
I do agree about the inaccessibility of desktop Linux (though it seems to be getting so much better these days!). A previous co-worker of mine uses AwesomeWM every day inside of a VMWare instance with Mac hotkeys disabled and loves doing that. Might want to give that a shot if you like what SizeUp gives you.
I used to be a Mac/TextMate zealot (Rubyist, go figure), and have wholly switched over to AwesomeWM, Vim, and a host of other open source tools and will never look back. I just feel like an incapable two year old with a messy desk trying to work in a floating WM like OS X/Windows now.
If you want to try AwesomeWM, but don't want to risk going crazy from setting up xinit scripts or scrapping all that vanilla Gnome install gives you, follow this wiki article and it'll side side-by-side in Gnome: http://awesome.naquadah.org/wiki/Quickly_Setting_up_Awesome_...
I get NetworkManager support, audio support, bluetooth, and battery life all out of the box. As long as you're not a purist about what's running in your WM and what's not, this setup works great with little risk/time investment.