All of my development is done on Ubuntu and CentOS VMs running in VirtualBox.
My actual IDE is often Eclipse (or Eclipse based) and I just make an SSH/SFTP connection to each virtualbox and the coding is treated as a "remote project" in Eclipse.
When I retire this Sony Vaio, I'm really thinking I'll get a 15" Macbook. Just for variety. There was a time when I'd never have dreamed of that. I bill a high hourly rate, I cannot be fumbling around because I'm on an unfamiler OS.
But I could switch to a Mac in 60 minutes. Downnload a JVM and VirtualBox for OSX, move over all my VM images, and I'm done. Back to work.
I chose Windows 7 because IMO it's the best OS available for me. I enjoy it. I never have reliability issues. I find I usually go 30, 40 days between restarts. It's nice I have this option: the chip and OS makers have really done a smashing job on visualization technology over the last decade.