I've had only 2-channel systems from high-end to budget system in the past and just purchased my first modern HT system. After a lot of research and deliberation I choose the Yamaha rxs740 Aventage avr. It is their entry level Aventage 7.2 yet uses all discrete electronics in the amp section. It has the ability to configure 2 surround channels for the front L/R to bi-amp the L/R channels in a 5.2 system. Very impressive.
Along with it I purchased their bds677 bluray/sacd player for music and movies. It is reported to have even better sound quality than its excellent video performance.
The sound is everything I was hoping for and more. The system is so revealing it is easy to hear the improvement in sound
stepping up from CDs to HDCDs to SACDs. Sound is very involving which I
thought was not possible w/ an AVR and Bluray/SACD player. I think I'm a
convert to surround sound, though I only am using a 3.0 system currently. BTW, movie sound is staggeringly convincing and powerful too.