I was going to meet the vampire in the graveyard and join them.
She is nowhere to be found and I don't want to join the theives.
Why? Is it perhaps that my reputation is now to high that she doesn't want anything to do with me? Anyone know?

Did you go at night? She will only be there when it is dark. And you did not pay the thieves yet since you do not want to join them, I assume. Reputation should have nothing to do with at this situation.

However, if you wait too long then the vampire will not turn up. You should go right after you receive the summons from Valen.
And yes, like Accord said, you should go during the night.

Yes, I went at night but I did about 6-7 quests first to build up experience
as I knew as soon as you paid her you entered a liniar section of the story.
Does this mean I have only the thieves to choose from now.

Yes I think the shadow thieves are your only option. There might be one last possibility, but you'd have to cheat. I haven't tried this out so I've no idea whether it'll work but you could go to the Graveyard at night and summon up Bodhi using the cheat codes (if you've the cheat mode enabled, press CTRL + Space and type: CLUAConsole:CreateCharacter("Bodhi") ). Maybe this will work but I'm not sure. You could also try summoning Valen (the one who tells you Bodhi wants to see you and try if you can get the quest from her again)

Can you actually create Bodhi??!! Well there's something that I never knew!

SPOILER...............






You actually get a good bargain with the thieves. But if you don't want to ended up being sucked of 10 levels then I suggest Bodhi is the right choice.

When you complete Bodhi's quest, you kill Aran Linvail for an item called the Elven Chains +1, this cannot be normally obtained by working for the thieves and it allows fighter/mages to cast spells.

Do you want it? If you don't then there isn't really much difference in the choices!