I am looking at making a little cluster of servers for class and as a practice area for working with servers. Even though it is not for production I want it to be able to work as if it where. This question is about what you as individuals have to say, not really a right or wrong or concrete answer needed. 2003 is a really good OS. Stable and dependable.2008 from the little I have been able to use it, the same applies. I have a few older servers that are only 32 Bit systems that I am going to be using in the set up and want to get a feel for your opinion and what you think would be best. Would using 2012 be beneficial or will it be too much of a pain? Would the interaction of the two 2003 machines cause more issues than it is worth dealing with, or do you think it would be a more realistic feel for how things will work in the real world? Do you think I should stick with 2003 and 2008 or do you think I should to with 2003 and 2012 or even have a mix of 2003 and 2008 and 2012?