How loud they will go is important. If he is worried about listening at reference levels at his listening position, then the speakers will have to go loud enough without compressing or distorting factoring in the loss in dB from the speaker to his LP. Most conventional speakers have a hard time doing this. Pro mid drivers mated to compression style tweeters mated to horns excel for HT applications. You need very little power to get them very loud.
Television: Mitsubishi WD65737 DLP
Processor: Emotiva UMC-200
Amps: Carver AV 806x/Behringer EP4000
Mains: DCM TimeFrame 600 Center: AT 453C
Surrounds: AT 251.1 Sub: Danley DTS-10
Blu Ray: Panasonic DMP-BD655