Tastes differ; I would never set 'ignorecase' as a default, and instead of 'number', which is only occasionally necessary and most of the time is visually disturbing, I'd set 'ruler', or a slightly more fancy 'statusline'. The most important one, however, for me is 'set guicursor+=a:blinkon0'.
I went back and forth with ignorecase until I discovered that placing \c in the search pattern will make that search case insensitive. This makes it much easier to do the odd case insensitive search but keep the default case sensitivity. (\C does the opposite if your default preference is the other way).
