My personal favorite is Osaka Grill. They have fantastic food at (mostly reasonable prices). When Kobe beef was available in the US they had it there. They now have the (not as good) American version. However, their chateaubriand is amazing and their shrimp fried rice is holy how crack good.
Also, if you have a few hundred to spend you could check out Masas. I went on someone else's dime and it was the best meal I have ever had in my life. The head Chef is Ron Seigal (first American to win on Iron Chef!!) and the man is a culinary genius.
If you like Indian food I HIGHLY recommend Naan N' Curry. I'm not a fan of curry for the most part, but their food is great. If you can handle the heat their Chicken Vindaloo will blow you away (and cause a ring of fire)...
For delicious general 'American' food with great service I would also recommend Postrio.
If you have specific styles or types of food you like let us know.
And I would highly recommend AsiaSF. I've never heard anything but good about it and it sounds like a blast (not been though). Of course take that with a grain of salt. I walk up Polk St to go home at night so seeing trannies is anything but new for me.
There are a LOT of amazing restaurants in SF. Ask away.

jr



"What can be asserted without evidence can also be dismissed without evidence." C Hitchens