Best software setup for Intel hardware

I gave up programming about 18 months ago, with incredible stability 
frustrations on WO5.1.x/Mac OS X Server. Now I've got a project that's 
too good to pass up, so I've been researching and reading the archives 
to see if I can dust off my WO knowledge and confidently implement the 
project in WO5.2.3 (it looks like many of the deadlock problems are 
solved, don't know so much about the crossed sessions). Now, the client 
doesn't seem to care what technology is used, but they've already 
bought the server - some 2.6GHz Celeron server from Gateway. 
Theoretically I can put whatever software on it I want.

But I am still ignorant on current deployment issues, and know nearly 
nothing about Java servlets. I am very familiar with deploying on Mac 
OS X Server and its command line, and MS SQL Server (on a Windows box 
set up by someone else). I have a little experience with IIS and 
Windows overall, and none with Linux. So which would be a more 
stable/manageable platform - Linux or Windows (and what flavor)? SQL 
Server, MySQL or Postgre? Tomcat, JBoss or something else? Deploy the 
"standard" WO way, or as a servlet? I'm not sure if I'll be able to 
change the OS (and it's probably Windows), but everything else should 
be up for grabs. If it makes any difference, the project involves 
uploading and managing a very large photo library (although the images 
themselves won't be large).

Thanks,
John