Also, something I like to do a lot (got it from Shawn Lane)...well, you have to look at how you're breaking up the arpeggio. In most arpeggio 'shapes', theres USUALLY one note on the string. In this case there two notes on the top and the bottom. If you're already for sure hammering on one note, why not add more? On the example finger cruncher posted (F major), you could say, rather than hammering on from 14 to 17,hit the 15 in there too, so it'd go 14 15 17. Then when you get up to the high e string, hit the 15 too. Can be done just as quick, gives a really cool sound with little extra effort. Or bring up your picking hand and tap the next note in the chord after you hammer on the 17th fret. Once again, little extra effort, big extra results. Or if you want it even quicker, and can stretch your fingers a bit, just hammer on the 20th fret. Not a big stretch in that position, but lower on the guitar neck, it gets more difficult.