The key to a successful Valentine present to avoid the typical gifts (anything covered in hearts and plastered with cheesy sayings, unless you know they will appreciate the kitsh value) and to think about what the recipient actually wants and/or needs, for the practical types. For instance, a new bottle of her favorite fragrance, or some kind of fun gadget for techies, or a decadent dinner at a restaurant you've both been dying to go to can be good ways to mark the occasion. Of course, the ultimate Valentine celebration would be to whisk them off on a romantic vacation, but that might be a little out of reach, or difficult to plan.
A good guideline to follow when shopping for any gift is to think about what the giftee might desire, but wouldn't splurge on for themselves. Anything cashmere can work, especially a plush robe. Luxe beauty items or grooming tools are also a good call, or a great bottle of wine (or their tipple of choice). Upgrading something - say, getting them a new mp3 player or a state of the art espresso machine - can be an excellent move as well. Basically, think about their interests and hobbies and get them the gifts that they will enjoy, not something you think they should have/use.
After all, choosing something like a high end shaving kit for a scruffy dude, or stripper-wear for a girl who's more conservative (granted, everyone has a wild side, but sticking with the elegant stuff until you know otherwise is a safer bet) tends not to lead to the most...romantic Valentine's Day.
If you need some more ideas and are in the mood for extravagance, check out 3Luxe's gift guide, and if you want to keep things environmentally friendly, try TreeHugger's green Valentine picks.
*Isn't that puppy precious?