i agree with those here using the combination-software setup. It's funny, the DC community here has really fallen in love with Everything and Locate32. I'm one of them...and I think we know what we're talking about here.

Anyway, I've been around and around on the desktop search issues over the years. And you guys know how unreasonably picky I am.
Windows Desktop Search:
I used this at work for a while because we use Outlook and it keeps nagging you for installing it if you don't turn it off. Anyway, it's decent, but nothing spectacular. Not the most flexible application in the world. I never had a real problem with it other than I was just not all that impressed.
Google Desktop:
I've only used this a couple of times. Again, not terribly impressed by it. I also don't like personally using too many google software unless they are really great (gmail, sketchup, earth) because google is too big for my comfort. I don't necessarily think google is a bad guy, I actually have no reason to think that yet, but their size just makes me want to avoid them if I can help it. Anyway, I've never really given GDS a fair shot, but from what I saw...meh.
DTsearch:
Awesome!! Love it. Expensive. It's a little too intense for casual use. But if you want features, power, or just to get it to work exactly the way you want it to, this is the one.
Archivarius:
This is the best bang for the buck. For most users I would recommend this one. It's fantastic, it's lightweight, it can probably read more file types than anything out there. It's relatively cheap, but not free like the others. Still, they deserve a little money for how nice it is. I rely on this one for my personal business. The only obvious downside to it is that it shows all document contents, including emails, in plain text, so the previews can be a little frustrating to read (like html emails). But I got used to it pretty quickly. What I really like about it is how fast and responsive it is. WDS and GDS are very sluggish compared to it. The Archivarius guys are good guys, I would say our community here would welcome them with wide open arms.
Ian, I didn't realize GDS was killed. That's very interesting. It's interesting that the company that is THE search company discontinued its personal search tool. Not a good feeling for me. If anybody can make a dynamite personal search tool, it's Google. They have all the right algorithms and resources. So killing off that product is a little suspicious. They probably just don't want anything to do with desktop tools if they can help it. They want to go all cloud. I hope they never get rid of their pop3 email feature, or google earth, or sketchup as desktop tools.