I don't really subscribe to just one of these classes when I play.
At the moment with my Skyrim (don't groan, it's the most current game I'm playing where this applies) character, I'm a Dark Elf (not sure if that lends anything to this) and I always have an axe in one hand and destruction spell in the other. My bow is always close at hand too. I will sometimes stealthily pick off opponent's one at a time, and will sometimes go in hacking with my axe and blasting further away enemies with a spell. In my (character's) spare time I will dabble in alchemy, smithing, enchanting and extortion. I guess I'll lean more towards the 'thief' attributes, but never entirely.
Maybe in a future playthrough I'll try to roleplay a character more specialised to one archetype.