For my job I mainly work with Java/J2EE and deploy to Weblogic with Oracle as the supporting database.
I have a few choices in how to setup my work environment and I'm going to explain here what I chose and why.
First off I'll start with my dev environment. I've been using Eclipse for several years now and with the Lomboz plug-in I have some nice JSP editing features, this runs on the Mac side of things and has treated me pretty well it has a nice CVS plug-in as well.
Next is my deployment environment instead of working with it all on the Mac side and because I have a license for Parallels and XP I went with using XP as my deploy environment this allows me a few niceties. First off the other guy I work with uses XP, secondly Weblogic, Oracle and my VPN client are fully supported on XP, I can also run Outlook to hook up to the client's Exchange server and not have to deal with Citrix or Outlook Web Access lastly it helps me to keep a stable client environment that I can easily backup. I've allocated 768 MB of RAM to the Parallels environment (My MacBook Pro has 2GB of RAM) and the seems to be enough to make everything happy. There were a few setting that seemed to help not slow down my computer as well. First is that I don't launch it via Quick Silver (it appeared that QS was the parent process and that seemed to make QS in general slow down) The other thing I did was set Parallel's memory preference to on 1000 MB and for the specific VM set it to allow Mac OS X to handle the memory
(screen cap from http://cavemonkey50.com/2006/08/speed-up-mac-os-x-while-running-parallels/ )
I write all of my code in Eclipse on the Mac side, build and then move the ear/war files to the Parallels shared drive which deploys to Weblogic without a hitch. So far so good if you have any questions feel free to ask.