Hmmm... depends on exactly what you're looking for. You won't find much exactly like those on the PC, but there are quite a few tactical turn based rpgs out there just in different styles. The recent
King's Bounty games play sort of like Heroes of Might & Magic lite with less emphasis on grand strategy or management, but improved focus on turn-based hex combat which to its credit King's Bounty does extremely well. Tons of units with their own special unique abilities, spells, abilities, and modifiers for every battle tend to keep things interesting.
And by the way if you've never played any of the
Heroes of Might & Magic series before that's definitely worth looking into as well. Sort of a mix between strategy game and rpg with turn-based combat segments. Some games in the series are better than others but overall it's just a brilliant franchise. 3 in particular although old is probably still the best of the series but really you can't go wrong with any of the games in the franchise, they're all damned good.
But if you want something truly 'hardcore' then there's
Temple of Elemental Evil, which as far as games go is probably the best implementation of D&D in a game to date. Light on story but with probably the best turn-based tactical combat I've ever had the pleasure to play in and rpg. Challenging as hell especially if you're not already familiar with D&D to some extent, but extremely satisfying and fun to play once you get into it.
Disciples 2 is also really good, I still absolutely love the games gothic art style and its turn based combat while a bit different compared to any of the above is still extremely fun and compelling. I've heard mixed things about 3 though and never tried it myself, but if you don't mind trying an older game look up Disciples 2, it's really good.
Games like Fallout 1 and 2 are turn based, though I don't think they're what you're looking for. Of course if you're willing to give rtwp gameplay a try
(Real Time With Pause, meaning it basically acts as turn based behind the scenes but gives the illusion of being real-time save for the ability to pause and que up commands.) then that opens up a massive library of PC games from Planescape: Torment and Baldur's Gate to Knights of the Old Republic and even Vampire: The Masquerade - Bloodlines.