BTW, I see you want vertical splits by default, just like me. Some of us on the vim list have been working on a new option called splitvertical that would open splits vertically by default (You'd use :horizontal to override). I'd love to have you try out the patch and send bug reports (it's been my production editor for a few weeks).
There's a bunch of different commands in vim that open new split windows. :help, :diffsplit, C-], and so on. I'd rather specify my split policy once rather than remember to type :vert or C-w v everytime. (I only found out about C-w v and C-w s after reading OP, so that exacerbated the problem.)
Imagine new plugins that split windows to open tree explorers or previews or whatnot. I'd like splits they create to automatically adopt my policy.
https://groups.google.com/group/vim_dev/msg/679fee5026967b82