Thanks for the replies! I'll follow up on a few things:

1. I completely agree about the importance of fit. It's impossible to pick anything definitively without trying them on, etc. For that reason, I need to find a place with good return policies. Our local LBS, LL Bean, REI, velowear.com, etc. all have pretty good return policies. I know it's not the most efficient way to go about it, but part of the gift is at least trying to narrow down the choices for her.

2. Riding style: most of her riding is likely to be around town and short to moderate road rides, probably 20-25 miles max at this point. She'll be riding with the kids (and may not even need bike shorts for those rides), and occasionally with me on longer road rides.

3. Shell: She's not quite ready for the full lycra look in public, so she plans to go the shell route (and definitely no undies ). But the good thing about this option is that she can ditch the shell whenever she wants. (FWIW, I wear baggy, two layer shorts without problems.) Thanks for the offer, Mimi--I may take you up on it!