It makes sense to consolidate, especially in the light of service hardening, such as clustering or mirroring technology. It's expensive, but can be better justified by hardening several instances prone to outage.
Charley Jones
A+, ITIL, MCAD, MCDBA, MCITP: Sql Server 2005 Adminstration, MCT,
MCTS: Sql Server 2005, MCP, MCSA, MCSE, MOUS, PMP
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