My favorite is Italian Val, thin-leafed, tall, the most elegant member of the family to my eyes. It moves beautifully in 24" tanks with some current, the last part of the leaves floating just under the surface. Not good for me in stronger current tanks. There is supposed to be a shorter version of this called Crystal, but for me it was identical to the standard Italian, have not retried from other sources.
Vallisneria spiralis is also tall (blooms pretty easily, characteristic corkscrew bloom stem/petole/whatever it is), wider bladed than Italian but the same height (2 1/2-3'). This is my standard Val as it multiplies so fast and is so hardy. In strong light (~3W/gal) with feeding and CO2 it becomes twisted, so mine may not be pure V. spiralis, but a reversion of the corkscrew cultivar. It will take stronger current, but still moves okay without tangles if well positioned. Absolutely requires water changes and prefers reset with thinning annually in normal substrates - it, like swords, is a gross feeder if the substrate is rich and for me weakens if left in place too long and too dense. (FWIW, growing it a 3" plain gravel bed prefiltered RFUG seems to help. One tank is over 2 1/2 years old now w/o thinning the sides and back looks great still, I just remove all the runners outside my imaginary boundary line, Twice again as long a time and I'll feel more secure about that technique).
Jungle Val - the monster in the family. I used it in the big tanks when they were up, even with the big puffer it was great. Even down to a 75 it can be spectacular, but quite unlike a normal planted tank - set w/either Jungle Val or Crinums along the back and one end (once a "wall" is formed, trim off all the out of design place runners), foliage covers the entire surface (both those plants get 6'), then carpet the rest of the tank w/Anubias b. nana. Both of those plants will do fine on RFUG BTW. Schoolers such as rummy nose, neons, black neons, etc are spetacular - you feel like you are snorkeling with the fish. I've also used the Jungle Val in similar tanks for the Flagtailed Portholes - but you need to keep most of the substrate clear for them to be happy, just some rootwood tangles for refuge and a few clumps of crypts or A. nana. I got bubblenests in the leaves, but no fry. (my water is too hard for them I suspect).
I've had no luck with the marbled red form of Jungle.
I have some trouble keeping the short contortion in short and twisted form. I suspect it wants more light than I normally use, likely CO2 and ferts comparably. Most of my tanks are moderate light ~2W/gal or a bit over, but almost all below 2.5W/gal - where I have to start supplementing carbon and the rest.
