Accepted wisdom seems to be only use HQ for aspect ratios greater than 1920×1080 (ie. 2k & up). That said, if there is high-rez media being used in your sequence then it makes sense that all media be the same codec. There are two advantages of ProRes over 8-bit uncompressed. ProRes is a 10-bit codec and it produces a smaller file. There is a whitepaper (I think) about ProRes. Try searching the Apple site (and the Cow) for ProRes.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.8 QT7.6.4 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 3 (FCP 7.0.1, Motion 4.0.1, Comp 3.5.1, DVDSP 4.2.2, Color 1.5.1)
Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN