I've always used Picasa until recently and find that although rather basic, it is the easiest to use and the fastest when searching, etc (as long as you've used tags, etc), I use it along with PhotoMe for other info.
Unfortunately it doesn't correctly display .DNG's from my new GX20 so I've been looking for something else and over the past week have tried ACDSee Pro 2.5, Expression Media 2, IDImagerPro and Lightroom 2. They will all do what you want (at a cost) and have features beyond Picasa (though I wouldn't be changing if DNG's were ok).
Personally I think I will go for Lightroom 2 from the above, just because it's the only one that doesn't run like a dog on my PC and Laptop (though it's no where as quick as Picasa).
Also, none of the above will correctly report the lens metadata (specifically, which lens you were using) - I have no idea why they all get it wrong as PhotoMe can correctly identify my lenses.
It looks as though I'm going to have to go through my photo library and re-tag all 10000+ images