There's one thing that really makes fluid stand out from other screensavers and that's its ability to work without overtaxing my system. For all of us that have high powered machines in excess of 1 ghz, this isn't always a problem. I, on the other hand, use my trustworthy tibook G4 400. Almost every other program of a similar nature taxes my system to the point that it's unusable. Fluid literally reminds me of a lava lamp. It comes complete with that warm feeling. And, better (or worse, depending on your situation) there's so many types of settings that you can literally spend all day seeing which you like best. And then, after you do that, you of course want to go back and find a new combination. It's addicting in a good way.
And now, the latest version lets you incorporate video into the fluid. I used my isight to see myself and my surroundings in the fluid! How cool is that???
Also worth noting are the number of themes that come with Fluid. Some programs obviously skimp when it comes to free versions only to unleash the power and fury when you pay the shareware fee. For some reason, the developer of Fluid is happy when we're happy. In this day and age of software, that's comforting. I had an unpleasant exchange just yesterday with a software developer after I emailed him with an opinion about what he's doing. It's nice to know developers like concepthouse exist.
Here are my favorite themes from fluid and why. I wholeheartedly recommend that you take the time to explore them all .. but just in case you are looking to get started quick, here's my picks (in no particular order):
Fluid Classic: Reminds me of one of those electronic fireplaces from the 70s.
Nice Fire: Mezmerizing! The color is terrific! If only the visuals on iTunes looked this good.
Dynamic7: What I imagine living inside a bag of gumdrops to be like.
Radioactive Goop: The most fun you can have with radioactivity.
Studio 54: Wild, just like it was intended to be.
Copper: I think I like the metallic color and the way it works with the titanium of my powerbook. Odd because I tried this one on my iMac and it's not as appealing ... because of the color of the machine. Maybe that's just me.
TopoMap: This one just makes my eyes spin. It's not as colorful as the others, but its neutrality is really well done.
Aqua3D: You have to love anything aqua. If you like the mac, it's almost a requirement.
Ice: Could be my favorite. It's cool looking, which is obviously the point. Again, another fabulous color combo to go with the silver of the titanium. Actually, when I have this on with my powermate pulsing next to it and turn out the lights .. it's sharp!!
Hopefully this information helps you choose fluid as the last screensaver you'll ever need or want. It's considered donationware, which means you are asked to contribute to the development IF that's something you want to do. I can only think of a handful of software products that I think are worth donations, and fluid is one of them.