Current Setup: 5.1 TV: 36 CRT Sony Receiver: Yamaha RX-V2400 (no HDMI ports) Front Speakers: Polk-RTi6 Center Speaker: Polk-CSi5 Subwoofer: Polk-PSW 505 Surround speakers: Polk-Fxi5 I plan to upgrade to TV: 65 inch Panasonic Plasma (This will be placed on a stand) Receiver: Yamaha RX-V3900 Front Speakers: I plan to upgrade this to Floor standing speakers and need suggestions (budget around $2000 for both) Center Speaker: CSi5 Subwoofer: Polk PSW 505 Surround speakers: Polk-Fxi5. Maybe extend to 7.1 Should I spend some extra money and upgrade to 7.1 ? Where should I put the Center speaker…On top of the TV attached to the wall, or below the TV ? I was looking at the Polk LSi series Floor standing speakers. However they are 4 ohm, whereas the rest of the speakers are 8 ohm. Will it matter? I appreciate your feedback.