I find humans too generic, and will usually play the least human race available.

But what do you do in group RPGs? 6 human fighters?

I generally prefer to play the class that gets the best healing magic. Failing that, I prefer to play spellcasters over non-spellcasters.

Also, in party-based RPGs, when possible, I like to include a non-humanoid in the party, or someone who follows drastically different growth rules.

I usually pick some kind of rogue or 'roguelike' spellcaster. I like playing unfair, hehe.

Yeah, I'm fond of Paladins for that reason. I tend to shy away from the "pure" spellcasters. I'm not fond of the "Congratulations, you're out of mana. You are now effectively helpless. Now be a good little boy and run away and hide while you wait for your mana to regenerate" scenario. I prefer classes that are not wholly dependent on limited resources.

As a Thief fan, I almost always play a sneaky character with some bow skills. As race I usually chose what supports this kind of character the most (Khajiit, I say).

I usually pick a human (or magically inclined humanoid) spellcaster, and then level them up in a hybrid sort of way to get skills in most things.
I find magic usually requires less effort :D.

For me it varies. I usually like min/maxing so pick a race according to the type of character I want to play. For example in Neverwinter Nights I had a Dwarf Monk :).

Indeed, it's really annoying.

If it is a single-player RPG, I want to play a character that can cast at least some magic because quite often the magic part is much more interesting and diverse with lots of spells, than just trying to decide whether to use a sword or axe, or try to find the strongest plate mail. And then you have to buy lots of healing potions and maybe some rechargeable magical items, while a spellcaster gets all those for free, and doesn't have to buy or recharge anything, after acquiring the spells.

On the other hand, I don't want to depend only on magic either, the character should always have means to fight even if he can't cast spells for some reason (be it lack of spellpoints and no means to rest, or someone has casted a Mute/Silence on me, or somesuch).

For instance, in TES Arena, a plain mage is fine because he can still fight quite well with a staff (Staff of Magnus), as long as you puff up the fighting skills. At the same time, you have access to all those useful spells, and you don't need to keep buying/recharging them in shops.

On TES: Daggerfall, I selected a Spellsword instead (which is like a lesser mage with some melee fighting abilities, I guess), just in case. I wasn't sure if a mere mage could have fought similarly as in Arena, some FAQs implied that a pure mage in Daggerfall should always avoid melee fight, which was not what I wanted either especially as casting combat spells in Arena/Daggerfall is quite cumbersome.

All in all, I prefer party-based RPGs because there I don't have to make the choice. I can have both kickass warriors, mages, healers and thieves, or even something esoteric like bards, all in the same party. Ah, Icewind Dale....

I used to always start with a Half-Elf Bard or Monk or some such and then give up and play as a fighter.

I tried a crit-based human rogue in neverwinter nights once (original campaign). Didn't help that just about every 2nd enemy in the game was immune to critical hits though :P

I like fighter-mage hybrids, but they aren't often possible in RPGs.
Choosing one or the other depends on how much the mage seems dangerous or the warrior seems slow.
In parties, however, my main character is always an human fighter, as the followers provide the missing skills.

In Baldur's Gate 1-2 I played a mage as it seemed there is a good selection of characters with good melee fighting abilities to choose to your party, starting from Minsc. I wasn't quite sure if spellcasters were as abundant, maybe they were...

As for the race, it doesn't need to be a pure human as long at it resembles a human in some way (like an elf or a dwarf or a gnome or whatever). I don't feel like selecting a lizard or an arachnid as my main character, even if it was possible. As a supporting member, maybe yes.

I recall I had some kind of lizard-type in my party in e.g. Wizardry Gold (aka Wizardry 7), and maybe Dungeon Master.