I would recommend reading the new PF Advanced Race Guide.

And with some hesitation I suggest looking at Fursona. But you will have to ignore the anime inspired tentacle-rape allusions.

Any BRP d100 system allows you to play monster races if the GM allows it.  My son played a Giant in RQ2.

The first question I ask whenever I'm invited to play in a fantasy game is "Can I play a Skaven?"

Someday it will happen.

There is a relatively healthy amount of support for Drow PCs in supplements such as WotC's Drow of the Underdark and Green Ronin's Plot & Poison.

Couldn't possibly have anything to do with a famous RA Salvatore character;)

There are two things that you should consider before having monster PCs.

1) Is everyone playing a monster?
2) What kind of campaign?

If you're playing a standard campaign but one person is a thri-kreen paladin and everyone else is a standard dwarf or human, you're going to have to think about balance a lot more than if everyone is playing similar monsters.

In 3.x, the reason Savage Species has a problem is that it doesn't deal with Monster Hit Dice very well.  

A PC is always treated as a character of a level equal to his total Hit Dice PLUS his Level Adjustment.  

For example, a 17 HD skeleton would be treated as at least 17th level; as would a 17 HD giant.  The thing is, a 17 HD skeleton is only a CR 7; a 17 HD giant is CR 11...  

None of those would compare to a standard 17th level dwarf or elf.  

When you use Moster CR, you want to look MOSTLY at CR.  You want to modify LA based on special abilites that you get a lot of use out of (like an at will power).  But roughly, a monster PC of CR x should be a good companion for a party of Level x 'normal PCs' with no monster races or templates.  

Let's say you're thinking about a CR 3 monster (let's say an Ogre).  According to the Level adjustment rules, you could play an Ogre as a Level 6 PC (4 HD plus 2 Level Adjustment).  My suggestion - treat it as a 4th level creature.  It's better than a 3rd level half-orc barbarian, but it's not as good as a 6th level half-orc barbarian.  Then if you're group is 10th level, advance the ogre by class levels.  So a 6th level Fighter Ogre would be appropriate for a 10th level party.

These same guidelines can be applied to other editions, but the CR isn't quite so easily derived.  That said, looking at the 3.x CR rating should give you a pretty good sense of where it'd PROBABLY land in 2nd or earlier editions.

Quote from: TristramEvans;571907The first question I ask whenever I'm invited to play in a fantasy game is "Can I play a Skaven?"

Someday it will happen.

Skaven are quite cool. Darn you for making me want to play Warhammer!