Most DVR cards (except maybe cheap some no-name ebay cards) will include software... and really, most vendors use one of two or three different types of cards, just with their own branding and usually locked to their own software. So the more important question is, what is the best DVR card/software *package*... and the answer to that is, "it depends" - mostly on your specific needs.
That said, we've been using the
VideoInsight systems for years and have found them powerful and reliable. They do tend to be more toward the higher end of the price range, but as with most things, you do get what you pay for.
As for limiting space used, that depends on the software. Some will let you designate the free space to leave, others pre-allocate the space used for recording, and still others simply fill up all the freespace on the drive(s) they're given. VideoInsight allows you to specify the maximum size for each video clip, as well as how much free space to leave on the drive.
I strongly recommend having a drive or partition dedicated to your video storage, though - the problem is, if you put anything else on the drive, that just takes away from your storage space, and thus the retention time. If you're not paying attention, and you fill up the drive with other stuff, you could end up with very little record time left for your video.
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