I've been totally addicted to these turn-based, squad on a grid games for over a year now.
I loved Warsong and Shining Force back in the Genny heyday, but games like Disgaea and La Pucelle on the PS2 got me back into the genre.

What are some of your favorites in the SRPG vein?

My list would also have to include Military Madness on the TG16 and the PS1 port (Nectaris)

Advance Wars and Fire Emblem are good games on the GBA as well, if not a little simplistic.