Does the story change in any way depending on which race you pick
.which race do you think is best ?

lol No.

Nords get a few race-specific lines dialogue (barely noticeable, though) but other than that it's all the same.

Just go with whatever race you want, it won't make a difference.

Races mean little in Skyrim when the grand picture is looked at. Khajiit traders are not allowed into towns and what not yet, you are if your a khajiit.

The only thing I noticed is comments from time to time. Bandits will taunt you that you'll make a nice rug if your a khajiit.

Nords will say "What do you want elf." in a demeaning tone of voice from time to time.

Just little things like that.

What about the fort filled with orks that you have to be blood kin or something like that if I was a ork would they let me in??

In a case where tell takes precedence over show and those that tell are shown to be hypocrites (the Caravans are skooma smugglers allied with the Thieves Guild, Ysolda trades in Sleeping Tree Sap) in a series full of unreliable narrators, it makes me think that the treatment Khajiit PC's get is pretty much how they'd be treated if they weren't with the caravans. In other words, I don't believe Khajiit PC's don't get special treatment.

But yeah, you're generally treated better as a Nord, too, but it also goes both ways. The dock Argonians are friendlier to you if you're Argonian, as are the Windhelm Dunmer if you are a Dunmer yourself.

Sticking to the main quest, however, nothing really changes regardless of race save for a few lines of dialogue.

It really doesn't matter. Races are for starting skills which are irrelevant very shortly and for role playing. Role playing is why there are races so you can be who you want and it won't necessarily alter your experience those choices are up to you. The only game changing elements are a few lines of dialogue, powers (which you'll forget about once you are unlocking shouts), I know you can hide in plane sight during a Thalmor quest if you are a high elf, and yes the orcs welcome you if you are an orc.

But I'd encourage you to study up on lore and role play a character, there's nothing worse than the guys who just pick the "cat" because it looks cool and kill every non-essential NPC in the game. Sorry that wasn't directed towards you, just letting out some frustration LOL.