The standard videotape used for most DV devices is called miniDV. It uses a 6mm videotape cassette. In addition to DV camcorders, miniDV tapes are also used in HDV cameras. HDV is an early high definition camcorder format unrelated to DV except in the use of miniDV tapes. A single miniDV tape can record 60 minutes of DV video with 16 bit audio. Although longer recordings are possible by reducing audio sampling to 12 bits, this isn't recommended as it will require resampling for conversion to nearly any other consumer format.
miniDV and Digital8 have for the most part killed off past tapes such as 8mm videotape. Unlike VHS-C, 8mm's home VCR equivalent of Betamax (and later home 8mm) was essentially forced out of the marketplace. While VHS-C can be played on a VHS VCR, 8mm formats require either a camcorder or very rare home VCR that uses 8mm cassettes. For Digital8 this is no different than miniDV, although since even Sony eventually switched to the smaller miniDV format, the Hi8 tape market will disappear as camcorders are replaced.
DV and HDV are consumer digital video formats that are recorded to miniDV videotapes using camcorders capable of transferring the recorded video to a computer via firewire. HDV however, is in high definition but uses MPEG-2 encoding, which is more efficient, and necessary to enable a reasonable recording time for miniDV tape, but is inferior for editing purposes.