I recently got Street Fighter 2 THDR, but I've never really played a lot of fighting games or any Street fighters, the only person I've completed the arcade mode with is Ryu, but i'm finding the game in general tough 

Ryu or Ken. 

Possibly a referance to shinden koto ryu and shako ken? 

"I recently got Street Fighter 2 THDR, but I've never really played a lot of fighting games or any Street fighters, the only person I've completed the arcade mode with is Ryu, but i'm finding the game in general tough 

So what is the best character for a beginner?

"

it's not a Street Fighter reference...

I've been practising with Ryu and doing reasonably well after 2 weeks of intensive training, so I think that would be a good place to start.
But yeah, try all characters and decide which feels most comfortable.

Also, didn't Gray Fox in Metal Gear Solid say that hand-to-hand is the basis of all combat?

just spam kicks with chun li and you will win probly %50 or more games.

"I've been practising with Ryu and doing reasonably well after 2 weeks of intensive training, so I think that would be a good place to start.
But yeah, try all characters and decide which feels most comfortable.

Also, didn't Gray Fox in Metal Gear Solid say that hand-to-hand is the basis of all combat?"

Chun-li is a good starter character, I always find. She's fast and her combos are easily accessed and have quite quick execution. She's not the best once you get higher up though.... still, by then you'll know what's what.

Plus, it's always somewhat satsifying to kick the crap out of one of E. Honda or Blanka with a wee girl. :)

Each character has a lot of complexity and depth.  I'd try nabbing a FAQ move list and then trying out each character in single-player.  Once you've tried it with everyone and have a feel for the difference between the speeds and variations on their projectiles. practice online or with a friend.  It'll take a lot of patience to get even halfway decent.  I've been playing SFII off and on for nearly a decade and a half, and I still have way more losses than wins.

Once you get down the basics, though, start paying close attention to the spectator mode when you're waiting to play online.  You'll get a great sense of what combos work well, what kinds of moves you can string together, and the timing of when or how to throw projectiles.  Good luck!

Ryu or Ken probably.

Ken, long range, close range, projectiles, fast, anti-air, ALL TOGETHER!