I think it really depends on what you want - if you just want a straight video replacement just get a standard DVD recorder without a hard disk. If you're more likely to want to do editing (for example, recording a whole series, taking out the advert breaks, and making it into a permanent disk, or if you're into camcording a lot and want to edit that) then a hard disk recorder would be better.
There's also an element of future proofing too - I didn't get a hard disk recorder because I believe DVD recorders are just a stop-gap. I needed a video replacement as mine was knackered and I fully expect to buy a hard disk recorder in 5 years time or so as I think these are the future. All we'll use DVD recorders for is making permanent copies - RW disks will be dead. We'll just record straight onto the hard disk all the time and then only burn a DVD if you want to keep something for ever.
So you can either pay a bit more now for a hard disk recorder (with a DVD recorder built in) that won't have a particularly big hard disk, or save some dosh and just get a DVD recorder now and then upgrade to a hard disk recorder in a few years when they'll be loads around at cheap prices with much more usefully sized hard disks. That's my plan.
If you really just want to record stuff off the telly, watch it then delete it, just get a DVD recorder.
Edit: Should point out that all my thinking is based on my research when I was buying about 8 months ago - prices and sizes of hard disk (and even DVD-RAM compatibility) may have changed substantially since then.
CJ's link is worth a read - that's where I got most of my info from when I was buying. Just browse the forums.