You could use the same brand throughout, but there hardly is any company which makes the best for every gear. Alpine makes really good HU & processors, but that's abt it, Pioneer makes decent HU & overrated for everything else, Sony makes the biggest pile of crap with heavy pricetags in the market, MTX makes good amps not speakers, JL Audio makes very good subs & decent stuffs for the rest ( thank god for CleanSweep! ), Monster, Streetwires, Daxx makes excellent cables, Focal, Morel makes superb speakers, Genesis, TRU Technology, JBL (Crown series), Butler, Prokick (ooops .. hahaha) makes great amps & yadda yadda yadda. Entirely up to you dude ;)