Normally, -v -v -final, but some people say -fast vis is just as good as -v vis. I know that -v vis will make the bsp file size smaller, but it takes way longer to compile.
Verbose means "more words" and it just shows every thing it is doing on the DOS screen.
I have said it before but -v doesn't influence the final product, just provides more text output at compile-time (this may cause the compile to take a bit longer). What vis compile to use depends on your map really, if you're using manual vis you could skip the vis compile completely (or do -fast).