Alright so i want to be a Mage/Assassin. I either want to play as an Argonian or Dunmer, Which one? and can you explain a little as to your choice? Thanks!

Dunmer would be my choice. Not only are you not a lizard, but you also get bonuses in assassin/mage-y type skills.

how will anyone else describing how they will play change/affect how you want to play?

the beauty of skyrim is that you just play. your character develops based on how you play. you really shouldn't need advice except for perks but again pick the ones that best suit/support how you are playing.

My experience in TES tells me races change little in gameplay, I use them for roleplaying purpose mostly

If you're havin' game problems, I feel bad for you son. I got ninety-nine problems, but a dragon ain't one.

I have always, since Morrowind, played Dunmer assassins. There's simply something about them that feels "assassin-ish".

I guess I was taken in by the whole Morag Tong/Mephala "thing" that gives the Dunmer a somewhat unique flavor when it comes to "murder-for-hire".

I wish I could be more help, but I'm quite biased and a lover of everything Dunmer.

I don't do alot of research, just buy and play. After 400 hours of FNV, I'm ready for this. Anyway, am I understanding correctly that the character creation is nerfed so intricately spending hours to ensure you have a non gimped toon you want isn't necessary because the game adapts to your play?

Bethesda made sure there is no difference who you play as.

No classes, no stats, all skills are capped at 100 and any race can have all skills maxed out.

This.