Up to you, personal taste and preferences. Also - eternal debate:
- guy IRL playing guy in game: normal
- guy IRL playing chick: pimpled teen with complexes who had seen real girls in .jpg
- chick playing chick: OMG, ITs HOT. Also, friend request for gamer girls are hot. Also, we all know it's a lie since all chicks are G.I.R.L.
- chick playing guy: normal, hiding from above
One type of players impersonates himself in game so he match the gender and immerse himself into the world, "I made this".
Other type of player create a character and roleplays it, picking race/gender that fits that fantasy, "I have created that".
There is a type "I play a bloke for I'm one"
There is a type "I play lass for I can"
There is a type "I play lass as a bloke for I'm not <probably will be censored but opposite to your gender> to watch bloke's stern"
There is a type "I play lass as a bloke for lass rear is eye pleasing"
So the question is: what you want your avatar to be? You? Or maybe fulfill some fantasy? Try something you can't have? Or dive yourself into the story?
For the record - despite being M I play F character. Because I can, because it fits my RP, because I prefer female companion. This is my choice and if you have a problem with that, well, it's your problem.
Oh, can't decide between two options? I once found perfect solution. Flip a coin.
But hey, do not rely on pure statistics - it's deeper than it looks.
Assign your choices, say:
- heads: bloke
- tails: cyber-goth chick
Flip a coin high and, before it lands, quickly analyze what you wish it lands on.
Pick that option since it's more desirable.