Personally, I don't think it would be easier on a win box....but I'm a linux admin.
I have 2 servers running on a tbird 900 with 512mb of ram without any problem. One server is 20 max the other is 24 max. I would think that 5, 2 player servers would be cake on a p4 2.2/1gig. Yes, I would screen them all and have them all setup to auto-restart (script). I'd title all the screens too...but I'm just anal about organization.