You know what I love about alphabet letter displays? Everything. I'm sure it's a lot of work collecting them, but so worth the effort. Considering doing one yourself? Here's an inspiration gallery for you.
• Heidi purchased the letters in Lincoln's room from a variety of sources: Michael's, Pottery Barn Teen, Anthropologie, JoAnn's, Kohl's, Etsy, Pier 1, and more. (And how cool is that "&zmp Z"?)
• Melissa's Alphabet Display was a diy effort as she painted and/or decoupaged inexpensive letters from craft stores.
• The variety of sizes and colors in this display make it all the more interesting.
• Lots of letters and a few numbers thrown in for good measure in Joshua and Finn's Slightly Retro room.
• Zara's parents used wood letters as a wall border near the ceiling.
• Don't want to collect the whole dang alphabet? How about a mish-mash of your child's initial like in Emmet's Room.
Must-See Small Cool Homes: Week Two
Beth's Romantic & Retro Residence
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Shaw's Original Fir...
How To Make Perfect Bacon in the Oven
How To Cook Tender, Chewy Wheat Berries on the Stovetop
I LOVE idea and have plans of my own.. Love that the L for Lincoln is the one that stands out!
I did an Alphabet Wall in my Dining Room! We LOVE it!!
http://girlinair.blogspot.com/2011/01/alphabet-wall.html
We did an alphabet wall in my daughter's nursery using all vintage letters. Everyone (including my daughter) loved it!
http://www.kaleyann.com/2010/08/vintage-letters/
I work in a craft company where I cut laser letters out of wood, mirror and acrylic all day long in every font imaginable - I love alphabet walls but know I would be sitting there trying to identify every font and material! Such a shame when you can't relax into such a lovely idea. I love the giant button as an O though!
@k.Ann - Love the vintage alphabet display you did in your nursery. I'm about 50% done collecting mine (and my son is already 2 1/2!), but it's so fun to have stories behind where each letter came from.