Picasa!

Picasa is a photo gallery program for your computer. It was originally made in the 80s and was always a bit dodge until Google the legends bought it a few years back and completely revamped it. Now it does kind of what iTunes does for your music - Organises your photos into easily viewable albums. It moves slickly and seamlessly from one to the next and even lets you touch up and add effects to photos as you view them - It's very slick. For best results buy an external hard drive from komplett.ie (they're Irish and very cheap) and use that instead of clogging up your computer with photos.

Here's the Picasa link:
picasa.google.com