I always play rogues in RPGs, or the closest equivalent. (Not the highwayman kind, but the rebel kind.) Unless the game makes them useless.

By the way, stealth-oriented characters tend to be frail, which annoys me, so I'll try to make a stealthy character who isn't entirely helpless in a fight, if at all possible. Balance may be overrated, but lack thereof is definitely bad.

As for the species, in a new game I'll usually choose human first, or whatever the "standard" option is. Later, whatever looks like it might offer some fun options and not conflict too badly with my choice of class.

Hope this helps.

I tend to play hibrid classes like paladin or dark knigth, almost always human. If they are the anti-hero kind, the better.

I generally play as a berserk-like warrior, training in heavy fighting skills such as axe or hammer skill when possible, and in stats I improve strenght, resistance and any physical stat.

Regarding species, I love dwarves (I mean the Tolkien or BfW-like dwarves, not the seven dwarves) and when possible I choose them for my character.

About character behaviour in storyline, I follow some kind of honour sense about any choice I have. For example, I never refuse a duel with someone who insulted me.

I often try unorthodox builds, whatever that may be. A warrior that only reflects damage or has a massive hp pool, a shapeshifter, an archer that imbues arrows with magic, a melee mage...

Unfortunately these sort of builds are often either weak, classified as gimmick builds, or too powerful which usually leads to nerfing the build to death since it's not considered an "important" build.

More generally, I enjoy playing anything but run-of-the-mill melee characters. I prefer flexibility and finesse over raw strength, so mobility and range are both good. That said, I will happily go with a melee powerhouse if it comes with some form of interesting twist.

Demoknight ;)

Former-human cyborg assasin.

As a class I prefer Assasin or Nercomancer.

As a race Il go with anything that can see in the dark , have great mobility or can concleal its presence.

The common exapmple would be a Ninja out for revenge and the most obscure one would be someting like "the thing" (from the 1980 movoie).

I always take the the archer class. Also I'd love to see a half beas as a playable race, like werewolves or the Charr from Guild Wars.

I like dwarves and warriors.  Partially this is because it allows me to accumulate my favorite varieties of swag--shiny weapons and armor.  I do enjoy playing other classes, though, depending on gameplay.

I like magic users in general, mage, sorceress, witch.
Not race specific, as long as the character has spells, deffencive and offensive then I prefer this class.

Normally human cleric/monk type of characters. Strong with hand-to-hand and melee combat combined with (divine) magic casting. If there is some alchemy /potion making feature in game I also make extended use of that.

Personally?

My favorite game persona is a wizard/mage with lycanthropy. (Not the kind that makes you insane. I question games with cannon that insist lycanthropes be 'insane in the membrane', because it does not fit with real germanic werewolf folk tales. At least the precatholicism versions.)

In old folk tales, the lycanthrope is neither evil, nor mad. Just different, with different ambitions and goals than those of humans, and human-like races, like elves. The idea of "lawfulness" is incomprehsible, for instance, outside of simple things like natural and pack laws. (Strongest eats first, kind of things.) Most sources of conflict in such stories involve hunters barging into the lycanthrope's living room and taking his stuff. (Cutting down trees, pasturing sheep, hunting deer, outright moving in without asking, etc.) The conflict of interest comes from the humans not recognizing the native inhabitant, nor his claim of residency, as valid. It is only later, after christian input on old stories that werewolves become demons that devour children in european stories.

That preface aside, my preferred game persona is that of an already somewhat aloof wizard, who purposefully aflicted himslef with lycanthropy for purely utilitarian purposes, and ended up getting more than he bargained for. (For LotR fans, think radaghast the brown, but with hair all over, with a similar disregard for human affairs.)

So, he is at once, magically and physically powerful, but lacking the desire to increase such, with nothing to prove, almost totally misunderstood by humans (but partially understood by elves), and interacts with the world of humans only on the edges. Views human expansion as a plague that destroys nature, but does not act. ("Nature takes care of her own affairs. Humans take heed!" Type philosophy on the subject.)

Spell set is not druid based. Actual mage spells, but rarely used for more than starting campfires, or freezing meat for the winter. (But well practiced in that respect.) Single, has no desire to procreate, nonsexual. Well educated from former life as a sorcerer, but intellectually changed as a result of the condition. Now realizes that trying to control or beat nature is a loser's game.

Since this type of character almost never exists outside of loosely run pen and paper types (a lot of DMs insist on such a char being druid class, for instance. I pick mage for a reason.), I usually settle for an ordinary spellcaster type, focus on practical magics, and pump physical skills.