Well, then you're in for a treat, Asafigow, because the GBA & DS has a shitton of great RPGs & SRPGs (Strategy RPGs ala FFTactics)...
GBA
Advance Wars - Great SRPG series revolving around a more modern warfare theme (instead of knights & mages you get soldiers & tanks)
Breath of Fire & Breth of Fire II - Great 16-Bit (SNES & Sega Genesis era) games. II is one of the best in the series even.
Fire Emblem (Blazing Sword) & Fire Emblem & the Sacred Stones - Another great, classic SRPG series, much like Advance Wars, only this one is the basic swords & sorcery stuff.
Golden Sun & Golden Sun: The Lost Age - Two of GBA's greatest RPGs. You should definitely check these out.
Mega Man Battle Network I-VI - Great series of games whose genre is part action RPG & part card battler (gameplay is better than it sounds, but can be hit or miss with some people)...Story's kind of campy, but I think still fun.
Riviera: The Promised Land - Probably my fav GBA RPG. Great series (Dept. Heaven) of uniquely styled games.
Shining Force: Resurrection of the Dark Dragon - Another oldshcool gem SRPG. The Shining Force series is a great step to take if you're new to SRPGs, I think. Gives you the basics in a fairly easy to manage way.
Tactics Ogre: The Knight of Lodis - Probably my fav GBA SRPG (and in general one of my fav games, I think). Lots of great customization. This is what FFT fans wanted when they heard about FFTA (which is ok in its own right).
Tales of Phantasia - Another great RPG from that bygone 16-Bit era. Kind of nerfed, but that's actually a good thing because the old encounter rate was GRUELING. The only in the "Tales of..." I've played, but I hear the rest are great too.
Yggdra Union: We'll Never Fight Alone - 2nd entry in the Dept. Heaven series. Interesting take on the SRPG genre.
NDS
Disgaea - Since you don't have a PS2, I assume you haven't played the other version. This is a great SRPG. One of the best.
Final Fantasy IV - This is the version of FFIV you should play.
Fire Emblem: Shadow Dragon - The first of the series comes out in English, finally. You don't need to play this one to get the other ones, but you might as well play this one since it's pretty good.
Mario & Luigi: Partners In Time - If you liked the other one (or, wait, did you play Superstar Saga for GBA?), you will probably like this one too.
Mega Man Star Force - The spiritual continuation of the Battle Network games. Minor changes in gameplay, but still just as fun a series.
Lots of great NDS RPGs on the horizon as well...