Help with processor decision

I've been using a Denon 3808 receiver as my processor ever since I purchased a Parasound A52 last year to power my system (B W 804d LR, htm62 center, M-1 LR surround, with b w 600 sub). I purchased an Oppo-105 a while back for the better video processing, DAC and multichannel out (for SACDs). I'm about 70% music, 30% ht/TV. I have started listening to a lot of vinyl recently, so I do need a more musical processor (and I don't really have room on my rack for a two channel preamp). I run a lot of music (usb) and video (hdmi) from my Mac mini server through the Oppo as well. I'm torn between the following processors:
-Parasound p7 (would lose the hdmi switching, but could use the Oppo)
-Marantz 8801
-Yamaha A5000
I currently use Audessey XT room correction with my 3808. My room is 14 w x 18 l x 9-10 h sloping ceiling with the LR speakers on the short wall, and it is untreated with suspended hardwood floors. I am a little indifferent regarding room correction, but given my room I think it's been helpful for HT. Between my cable box and a possible xbox purchase, I may need more hdmi switching than the Oppo provides...
Any advice would be greatly appreciated since I plan to follow-through with a purchase THIS WEEK!
P.S. This will probably be the first of several upgrades in the near future (adding 2 surrounds to get 7.1, adding more powerful amps for my LR, upgrading center and sub).
Try the inexpensive Radio Shack SPL meter. It comes with simple instructions and is totally adequate for the job. I assume you use the excellent analog output of the Oppo 105, because that's what distinguishes it from a 103. Many posters on the Oppo 105 owners' thread at AVS would argue that a direct connection to the amps will be superior than through any of the processors you are considering. The analog processing of the 105 really is good, so even if you use a Marantz 8801 you might want to go around it for stereo.

Bebopmecha5: You're quite welcome and glad to be of assistance. Your first post was a good one and well stated. Yes I agree with Dbphd that the Radio Shack Sound Level Meter is more than adequate & very affordable. Let us know how you like the Marantz surround sound processor. I wish I could afford that but with a 20 year old son in college....well that explains it !! Keep posting.
Thanks again for the input, and I've got the Radio Shack sound level meter on my short list in the near future. I'll definitely play around with the setup with my Oppo and will try to compare directly connecting it to my amp. I definitely use the Oppo dacs and analog outs for music (2 and multi channel), and use the hdmi for tv/movies. The Marantz should arrive next week so I'll circle back and let you know my thoughts. I just received my xlr cables from Blue Jeans Cables (talk about fast shipping!) so there will be some significant upgrades to my system soon!

Here's what i've found to be the best method of getting outstanding performance between the 8801 and Oppo 105. Assign the 8801's Cd input to the XLR's for the Oppo's XLR outs for stereo and use the Pure Direct mode for 2/ch this way you can hear the outstanding 2/ch preamp abilities of the 8801 ( I find it a hidden gem) Also set the Oppo to bitstream for hdmi ( using the hdmi 2 out as hdmi 1 will not send DSD) and set to DSD as the 8801 will accept a native bitstream over hdmi after that and a good run of Audyssey you have a killer 2/ch preamp and multi/ch processor setup to die for !

Enjoy your new setup
Thanks for the advice Jdub39. I'm definitely using the xlr out on the Oppo so I can take advantage of the Oppo's dacs. I'm actually also using the multichannel analog outs on the Oppo for SACDs. I will definitely plan to try out the hdmi out for SACDs as well to compare the 8801 dacs with the Oppo's. I just figured I already had the analog cables from my previous setup and thought I'd just connect them all at once... I just ran the full Audessey setup and I've tried out a few bluerays (star wars 2, Dave Matthews at radio city music hall) at reference levels as well as an SACD (holst planets) and some vinyl (police, Chet Baker). I'm still getting used to the sound of the 8801 but so far I'm definitely getting the sense that there's a lot more definition in the sound and more control in the decay of notes. I've still got to figure out all the detailed settings for viewing and audessey, but so far so good! Any experience with burn in time for the 8801? I've noticed the 8801 gets pretty hot, even on my open rack, so I figure burn in time should be short... Will report more soon!