Have a look at the cheap eBay intervalometers - they let you do very long exposures (using bulb mode on the camera) and also work as a normal remote release.

I have one for my Nikon DSLR - It was around £12 or so, and (other than having a camera cable with an inline mini jack connector so you could use the same device with different camera connectors) it's virtually identical to the official Nikon version I had before (which was £100+). Functionality and display are identical, and the housing looks the same apart from branding, so I suspect that Nikon OEMed theirs from the same source.

I've also had a few standard wired remote releases. The branded ones are usually more expensive, but the third party ones worked fine. Only real difference was that sometimes the branded version had a nicer camera connector (in the case of my Nikon, the branded one had a screw on retaining ring, while the (far cheaper) third party one didn't - but worked fine anyway.

But given that the intervalometers aren't much more expensive than a standard release, and can be used as a standard release, that's what i'd go for. Just make sure you get the correct one for your camera model (Nikon have used a couple of different connectors for their cameras).