Since I am just playing around, price tag is more of a concern for me. :) Like this one: http://www.microcenter.com/single_product_results.phtml?product_id=0363874
I guess you might need high-reliability system with backup RAID etc. It doesn't need a very fast CPU, but should be easy to maintain. Maybe you should search for an old server.
Sorry I am not an expert on this one. The lenovo machine is not very good by all standard.
