'50s Valentines - A Flickr set of 58 (historical?) images by valart2008 that beg to be passed out in class.

This link goes to a page of thumbnails. Click on one to see it, click "All sizes" above get a version big enough to print. (You might print a sample to get an idea how large each size would print.)

Concept counts: Idea: Scientist Valentines at Ironic Sans.

Click to enlarge, then print, fold or... wrap around chocolate.

Less mush, more bite:
Hearts Atwirl Vintage Valentines is one woman's private collection. Definitely worth digging into.

While that first set takes me back to third grade, Elizabeth Rosenberry's Valentines are stranger, and more interesting. If you're on the outs with your sweetie, here's one for you. There's tougher love, too.

Like ornate? Vintage Valentine Postcard Gallery from Pamela Wiggins, Antiques Guide for About.com.

Virtual V's: a good surprise. I wasn't expecting a guitar-playing cartoon rose and a toe-tapping heart belting an upbeat R&B tune at an earnest site:

"For every eCard sent, Care2 makes a donation to an environmental nonprofit to save a square foot of rainforest."

The rest of their Valentines. There's a "love" section, too.

Bonus thought: Abe Lincoln turns 200 today.