Processor platform for Terminal Services

I am planning a server hardware upgrade for a current server with dual Xeon 1.8GHz processors running Windows Server 2003 Terminal Services supporting about 15 users. I might be able to budget Citrix licenses if I avoid another dual processor system and going with a fast dual-core. Dual processors -vs- dual-core? Can anyone tell me which platform would compare best for a Terminal Server if, in fact, there are considerations for this?