I also tried BD Sizer and must say it's quite nice yet minimalistic. What I like about it is that it does only one thing but does it well. You can simply drag and drop all your images on the desktop icon to resize them. What I also like is that it allows you to set the file size you aim for. This is very handy for forums.
But for other work, I feel a more powerful program is in order. I tried Lightroom. While it is quite nice, it is also a bit counter intuitive as they do things very differently than all the other programs out there. For a simple catalog/sorting program that does basic retouching, I use Picasa.