SD is pretty dead at this point. Get HD if you can.
As far as memory goes there are a few things to consider, as far as quality goes last I checked tape was still king but the video used on flash cards is approaching it. You can fit 14GB of data on one $3 mini-DV tape.
They record at a higher bitrate than the flash based camcorders. The video is also easier to work with in editors. One downside is transfer to your compute is done in realtime so if you have one hour of video it's going to take you one hour to transfer it.
Another thing to consider is that once the flash card is filled up you either need to transfer it to a computer or have another very expensive flash. With tape you can juts pop another tape in. With flash you're recording time is very limited. I have two 6 hour batteries for my camcorder so I'm good for 12 hours in the field.
I really like tape because it forces me to keep a backup, once a tape is recorded I transfer it to an external hard drive for easy access from computer. The tape gets sent to a relatives house for safe storage as a backup.
As an aside I see many of the better still cameras are offering the same recording capability of camcorders. In the past video on still cameras was really poor for anything but a novelty. That is not the case now, they are using full quality video comparable to regular camcorder.
My brother picked up a Canon HV20 about 2 years ago and it has worked great, current model is HV40.
Canon | VIXIA HV40 High Definition Camcorder | 3686B001 | B&H
A good place to check for reviews is
Camcorders - Independent Camcorder Reviews, Ratings & Comparisons