I never use spaces, it always seemed backwards to switch to a whole new context just because I want to access a single app. What if I want to look back at some code I was writing while I'm IM'ing someone? What if I don't want a whole context switch, and I just want to send a quick message? What if I don't care what space an app is in, obviating the need for all this crazy Mission Control complexity?
All I do it bind my most frequently used app to hot keys (Cmd-F1, Cmd-F2, etc.). When I want to use an app, I pop it open with Cmd-F#. When I want to close it, I hit Cmd-H to hide it.
If you mainly work at the granularity of single apps, I could see that. I tend to use groups of apps, so without spaces I waste way too much time re-assembling my working contexts. With spaces I can just swap in a whole context, like "programming": my text editor, a terminal, and a browser open to a relevant doc all pop up as a group, arranged how I want them. And stuff not in the "programming" context disappears instead of cluttering my screen.
If I have to do this app-at-a-time, I need to bring to the foreground Terminal, MacVim, and Chrome, each with a separate hotkey press, then hide everything else. I admit this working pattern may be specific to a Unix style of "IDE" made up from multiple apps used together, though. If you just use XCode or Eclipse or something, it's already bundled into one app so maybe not an issue.
I use Terminal, Emacs, Firefox, etc., pretty much the standard setup.
The programming environment is the only bundle of apps that need to be specifically arranged for me. They pretty much always sit positioned where I want them, and I bring up other apps when I want to do other stuff, and hide them when I want to get back to programming. I never really hide my coding apps; I just bring other apps on top and hide them.
It's nice too to always know that Cmd-F1 will bring up Firefox, no matter what is going on.
But this is definitely a user preference thing, and specific to how I like working.
How do you bind "switch to app X" to a hotkey? I'm in Keyboard Shortcuts, and I while I can see how to define shortcuts for app menu items and such, I don't see how to specify switching.
I agree with you on the context-switching issue in spaces- it seems counter-productive to have to switch to a separate space for email, terminal, whatever. I like being able to have all my apps in the same space (albeit on two physical displays), and Expose and Cmd-tab seem less disruptive to my workflow than Spaces.
I don't know of any option for that built into the OS, but a number of third party tools can add it. Quicksilver triggers are my method of choice, since I'm running Quicksilver anyway.
I could never get into multiple virtual desktops either. No matter how carefully I arrange my windows into different spaces I always end up with a scenario where I need to re-arrange windows to fit whatever task I'm working on. Ends up being a huge waste of time for me. The only benefit I get from spaces is a clean looking desktop but "Hide Others" solves that problem fairly well.
All I do it bind my most frequently used app to hot keys (Cmd-F1, Cmd-F2, etc.). When I want to use an app, I pop it open with Cmd-F#. When I want to close it, I hit Cmd-H to hide it.