I've been seeing huge variations in the amount of memory people allocate to their Parallels virtual machine. I run Windows XP via Parallels full-time on both my Macs, and out of 2GB memory in each of them I set 384MB for Windows. This is sufficient to run Outlook (for Exchange work email), uTorrent, Office Communicator (also for work), and a fourth app such as Visio, DB Designer, or Visual Studio. I see people allocating a full 1GB to their Windows VM and I have to ask...why? What the heck are you doing in Windows that warrants a full gig of RAM? Mine runs pretty darn well with 384MB and it's even usable with 256MB. I know it would be somewhat better with more RAM, but are you really willing to sacrifice memory from OS X? I can easily eat up most of my 2GB of RAM in OS X when I really get going, and 384MB for XP/1.625GB for OS X seems to be a great balance. I'm just curious about other people's thoughts.