There are so many different strike indicator "systems", you will have to try and find the one that suits you bests. I like the foam indicators (the ones with a o-ring), but they can be a bit cumbersome to cast with a 3wt. You could get one of those strike indicator kits which have a couple different ones and give and test each indicator until you found the one that fits your bill the best. One note: while the frog hair indicators are in theory a good idea, you only can use them on a permanent nymphing rig - if you want to change to dry flies, you will have to throw the indicator away; you can't re-use it.
That's my 2c.