Peter Bohush likes smooth camera moves, and he's written up a piece on sliders, and added a video to go with it which shows using the slider, and also has some examples of slider shots.
He likes Igus sliders, which are inexpensive; and you can get some of their models on Amazon; just watch out that some Igus models don't have a screw-whole on the top of the carriage (you have to do that for yourself!)
NewEnglandFilm: Camera Moves Using Sliders - The Dolly Alternative
Amazon: DryLin® W16-C Linear Motion System with clamp for Camera Sliders [$207]
Amazon: DryLin® W1080-A Linear Motion System for Camera Sliders[$131]
Igus: Camera and film technology
Chad Soriano bought an Igus slider because he couldn't afford the more expensive models that are out there, and he likes it a lot. NOTE: He bought the W1080-B which has pre-drilled holes, but is currently unavailable on Amazon [Igus says they will have more available soon]
You can read his review here: IGUS Drylin Camera Slider Video Test Review
Glidetrack sliders seem to strike a middle ground in price and features, and now they've announced the Glidetrack Hybrid:
New Hybrid bearings offer a combination of both sliding AND roller bearings, giving you the best of both worlds. It includes an open architecture design that uses individual greaseless self lubricating plastic bearings and liners that can quickly and easily be swapped out if required.
It's unclear when this will actually be released [the website mentions unprecedented demand and the need for a larger server?! -Ed] but they say there will be a 10% introductory discount offered.
Glidetrack: Hybrid Announcement
Meanwhile, late last year, Daniel Freytag reviewed the current SD model:
in my opinion the Glidetrack is a solid and very mobile slider for the beginnerFreytag-film: Ready! Glidetrack! Action!
B & H: Glidetrack SD - 39" (1m) [$309.95] Base model
B & H: Glidetrack Shooter HD - 39" (1m) [$429.95] Doubles as shoulder support
B & H: Glidetrack HD - 5 ft (1.5m) [$469.95] Heavy-Duty model