What features are you looking for in an 'organizing software'? Do you want to tag your images and be able to quickly search them out? Do you want fast viewing etc...or just organization?
I don't use a specific software for organization...but I do have a file structure. Personal photos get uploading into a folder named for the date. Then I have sub folders for files converted from RAW, files for working on, files for print and files for web.
Professional images are kept separate from personal images and in folders with names and dates...but the rest is similar.
I don't tag my images or anything like that...so I don't have a good system for finding an image if I don't know when it was taken...but it hasn't been much of a problem so far.
To find images, I usually use Irfanview. It's a free program is very light on system resources. It can even view RAW files (with the right plug-in). I've also used Google's Picasa, which does allow tagging etc and is great for quick searching.