Yes, I would take her to try on bands. You can often get better quality for a better price online, but it is always best to go try them on to see what she likes best! Go to a nice jeweler, though, so you can compare prices of better quality ones.
I have a classic 6 prong Tiffany style solitaire and I wear 2 bands with it. A plain Platinum Tiffany Bezet and a .33 eternity band.
Tiffany has lots of great bands that go with a solitaire if you plan on getting one from there. Is she going to be involved picking her band out? I prefer to actually try them on myself to see what I like best on