I usually play as Human Races, since their facial hair options are leagues better than their Elven Counterparts. While I am particularly fond of the Beast Races, I hate playing as them. Humanoids with tails have always been aesthetically off-putting to me.
I honestly never pick a race for their combat bonuses; I always focus more on the role-playing aspects.(Appearances as well.) I believe that the race I've played the most is actually Imperial. I've always enjoyed forming Imperial names, and their Romanesque culture and Mediterranean looks are appealing.
For me that would be Kajits Argonians, or Orcs. Haven't played any of those. Unlike Oblivion and Tamriel, Skyrim is not cosmopolitan in terms of how it treats foreigners. The only ones that are tolerated are Redguards and Orcs. Then it's mostly Redguard women who you frequently find married to Nords in encounters throughout the game. Odd that there is no half Orc/ Redguard choice in the character creation screen in the OC. I find Wood Elves useful for their sneaking, lockpicking and archery skills, but Redguard is are pretty useful warrior alternate choice with some nice spell default support
Most of the time it's a Nord for me who looks pretty stupid as a magic user and top dog at the College at Winterhold. Wearing a robe and casting spells as a Nord is pretty anti role play
Racial skill bonus's are only useful between the levels of 1 - 5, after that most characters will have 'smoothed out' and that +10 sneak that khajiits get at the start will become less attractive.
An orc can inflict a more lethal sneak attack than a khajiit with berserk. A high elf can potentially cast muffle at level 1 making them soundless sneaks.
Basically Khajiit don't offer enough for many players to consider them a strong choice...