Julius Jones wasn't a resounding success in his first season and though I think Jim Mora and company will give him a second shot, I also think Seattle will add running back talent through the draft. Seattle's next back should be cheap, fit a one cut zone blocking system, have some top end speed and pass the Tim Ruskell sniff test.
The name that springs to mind for me is Glen Coffee. Coffee is projected to go in the second day. Exactly when depends a bit on how he performs at the Combine. Cracking the third would be an accomplishment. He's a one-cut rusher that brings a little fight to the defender. You'll read knocks on his size, he's ~6'1" and plays at ~200, but Coffee ripped up his local Rivals event.
Ht: 6-foot-0 
(Event)
Wt: 195 lbs 
Forty: 4.44 secs
Bench max: 380 pounds
Bench reps: 22 
Squat max: 500 pounds
Vertical: 36 inches
Shuttle: 4.25 secs
ACT: 22
Class: 2005 (High School)
It's the TRST where Coffee separates himself.
Let's do this.
Games Played In: 35
Conference: SEC
Considered a Team Leader: Won the2008 Derrick Thomas Community Service Award
Production: 233 rushes, 1383 yards, 10 TDs
Second Ranked Rusher in the SEC
More YPC Than: Knowshon Moreno
Team Record in 2008: 12-2
Known Weaknesses: Size,Fumbling, Flash
Religious: Highly
Instantly Improves: Seattle's running back depth
Mmmm...coffee.