CC abilities like grav well and tractor beam repulsors are probably the most useful Sci powers for most queues. Heals are also useful, sometimes, as are drain abilities, although to make a drainboat work well you've really go to spec completely into it.
Comments
A Science ship that cannot Gravity Well 3 is no Science ship at all.
polaron weapons (normal, phased or dominion)
plasmonic leach
deflector with high flow caps (jem hadar, KHG)
aceton assimilators
Flow caps consoles
Tykens rift
energy siphon
tachyon beam
2-3 deflector doffs
gravimetric scientist doff (tykens rift variant)
for example. If you are interested, I can get more specific. What ship do you want to fly?