1. I
2. II
3. III
4. IV
5. V
6. VI
7. VII
8. VIII
9. IX
10. X
11. XI **
12. XII **

1. I
2. II
3. III
4. IV
5. V
6. VI
7. VII
8. VIII
9. IX
10. X
11. XI **
12. XII **

1. I
2. II
3. III
4. IV
5. V
6. VI
7. VII
8. VIII
9. IX
10. X
11. XI **
12. XII **

I found this interesting observation on the rec.music.makers.piano. It was written by a jazz pianist/teacher, but I think it's very worthwhile and applies to strings:

Why Practice Scales:
There are many possible answers, depending on your background and your goals. For a complete beginner, they help build finger dexterity by giving you something to play that you can work on without being slowed down by reading. They also teach you what notes are found in each key, which makes reading music go more smoothly as you'll cease having to read each note one at a time and start to see patterns within the key. If you're planning on playing jazz or any other style with improvisation, it teaches you what notes are available for use in improvisation, and teaches your hand good fingering habits that will hopefully come into play while improvising.