Spellforce offers the promising blend of RPG and RTS elements. Unfortunately, the game simply isn't very exciting. The plot moves along at a snale's pace, the unit/resource production is tedious, and the empty maps are barren of any personality.
The game's biggest problem is that there are relatively little RPG elements to the game, and the much more prevalent RTS elements are stale and dated. One interesting feature the game does have is the unique method for gaining new unit types; unit plans must be discovered in chests or on bodies. Unfortunately, this is the only highlight of the game.
While hardcore RTS fans will probably enjoy this one, others should stay far away. Get Lords of Magic: Special Edition instead. That is a game that truly combines RPG and RTS (or RTT) elements to create something truly engaging.