Center channel/L/R matching ?

[canuckle]

OK, so the resident experts here seem to be Big Daddy, Crackin, and Ozzman, so I'm pleading for some advice here.

Current setup is this:

Panasonic TH-58PZ850U
Sony STR-DA1000ES
Panasonic DMP-BD55
Bell Express Vu 2942 Dual Tuner HD-PVR
Speakers F/C/R - NHT SB1 (bookshelf)
Speakers SR/SR - Mirage OmniCan 6 (in ceiling)
Sub Mirage Omni S10

Here's my plan...in the next 12 months I plan to replace the L/C/R, and upgrade to tower speakers for the L/R. Center will have to be horizontal, as it will sit in the stand below the TV, no choice there. Total budget for the 3 speaker upgrade will be 1500-2000.

HOWEVER...

I can swing upgrading the Center now. Here are my questions:

1. Do you agree with upgrading the Center, then L/R later?
2. What would you suggest for choices in the 300-600 range for the Center, with an eye on buying matching L/R later?
3. The Sony 1000ES allows EQ adjustment for L/R, but not Center. Problem? Each speaker's level can be adjusted individually.

Thanks for your consideration guys.

Mike