It really depends on what music you want to play. If you're into classic rock, pentatonic is probably enough. If you're into metal, you'll also want to learn the natural minor, harmonic minor, and phrygian scales. If you're into jazz, I don't have enough space to list the stuff you'd benefit from learning. I think the best thing to do is learn the theory behind scale construction, then you can figure out your own fingerings instead of learning them from someplace else, because you're more likely to forget if they are just fingerings to you and not notes. For improving speed, the key is to play slow. I know that sounds stupid, but people who play their scales as fast as they can are usually not playing them perfectly, and if you play without mistakes, it's a better way of improving speed in the long run, and its a better way of having technique that you can use. Who cares if you play really fast but sorta sloppy? A lot of people say this, but you really should take it to heart, find out what you think your fastest comfortable speed on the metornome is, then practice everything about 10 or more bpm slower than that, and you'll improve way faster. When learning something new, practice way slower.