Does anyone have any good, balanced d20 stats for blaster-type energy weapons, either personal or artillery-type?
PL 6 has laser weaponry.
http://www.dandwiki.com/wiki/MSRD:Future_Equipment
If you're talking otherwise modern, than the purchase DC goes up by 5. I think. It might be ten.
Star Wars Saga edition has some powerful but balanced stats for blasters. 2d8 for Blaster Pistols, 3d8 for Blasters Rifles and 3d10 for Heavy Blaster Rifles.
Sounds like a lot but when you factor in the fact that there isn't a D&D style magic with the ability to increase the damage over time (like making your sword Flaming), the Star Wars method is pretty balanced.
Flaming laser pistol!
... sorry