i believe it's all about the style and you don't want your guitar above your chest of course! it all boils down to the style of music you play... i sum up in 3 catagories, that are;
1. way way up - impellitteri, yngwie (full-shred and some indy as well)
2. mid - greg howe, richie kotzen (shred with style)
3. low - slash, nuno, page (pure style)
as marty friedman said, you will never score chicks above catagory 1. (j/k)
picking angle changes when you are standing up, and it causes problem when you try alternate picking... i am going for no.3 and i tell you... it's hard unless you've got a gifted long portion of arms.