Photo Software

I was jsut wondering if anyone could recommend any (preferrably free) digital photo management software.  Right now I use IrfanView, which is great for viewing, but I'd like something to organize them better.  Right now I sort my photos into directories according to when I took them, for example, when I download from my SD card, they go into a folder named according to what most of them are pictures of followed by the date).  But I'd like a way to "tag" my photos as well, for example, to find all pictures of sunsets or my friends or myself.  I've tried Google's Picasa, but didn't like it for two reasons.  (1) When I installed it, it immediately started scanning my entire computer for image files, when all I really want is to manage my digital photos (which all reside in subdirectories in one master directory).  (2) It had a label feature, but creating a new label forced me to give it a date.  As mentioned, I'd like to be able to label/tag things according to subject/content, regardless of when they were taken.  So, anyhow, any suggestions?

I use Xnview, but it's a pretty clunky looking software. Gets the job done though, and pretty pacey. It does have a tagging feature, but I've yet to fully use it. Give it a try, it's free, and has a low overhead.