As a wish list - I would ask for two systems (clustered) running Windows Server 2008 x64 - 64GB RAM and 4 hex core processors to host SQL Server 2005/2008.

I would also bump up to Enterprise Edition - if you are not already, there are quite a few features in the enterprise version that you will need for a data mart/warehouse environment.

You could use both nodes - one as your SSIS node, the other for the the database and SSAS (if you are using that). However, that would mean additional licensing costs 😉

With that kind of system - you could run everything on a single node, but you would only do that during maintenance cycles and/or emergency situations. During normal business, you would have quite a bit of resources to process the data and perform your extracts and loads.

That's what I would be asking for...