The Fire Emblem games are fairly traditional fantasy strategy RPGs... I think the first game in the series (for the NES, never released in English) may have been the first strategy RPG, period. The series hasn't changed that much since then, so in some ways it can seem like a bit of a regression, but it's fun if you like old things.
Anyway, for the GBA, there are a few more that haven't been mentioned...
Yu Yu Hakusho - Ghostfiles - Tournament Tactics is a strategy RPG based on the anime of the same name, but you don't have to have seen the anime to enjoy it. It's pretty fun, anyway.
Onimusha Tactics is a strategy-RPG loosely based on the Onimusha series. Sort of fun. Status effects are overpowered in this one for some reason... they never fail unless the enemy is totally immune to them (and few are; even several of the early bosses are vulnerable to sleep.) Still, that's fun, too, in a way.
Both of the above are fairly traditional FFT-style strategy RPG games, aside from their own quirks.
Also, the Super Robot Wars games (Original Generation and Original Generation 2 are the only ones released in English.) They're very, very good strategy RPGs, although they're sci-fi themed instead of fantasy.
For the DS, there are fewer options, and the most obvious ones other people have already mentioned. For one other game that's often overlooked: Battles of Prince of Persia is fairly strategy-RPGish... you don't keep your units between battles or level them or anything, but it still have a strong strategy RPG vibe. (You collect cards and use them for various special abilities in battle instead... it's better than it sounds.) Anyway, it's better than you'd expect, and not just a license cash-in. (That goes for the two games above, too.)