At the moment my seven's tuned AbDbAbDbGbBbEb; basically drop C# with an extra low string. That's one of my favourite drop tunings, mainly for its versatility. The default tuning on that guitar's Bb standard, although I love to play with different ones. ADADGAD's another great one, as is CFBbEbGCF.
It's all a question of personal preference. I know plenty of people who like to stick to standard because they don't like the sound of dropped or open tunings (Durero takes it one step further and tunes the whole guitar in fourths to make it as systematic as possible), but I really like the way a switching tunings forces you to looks at the fretboard in a new way and possible come up with something you wouldn't have thought of otherwise. Just tune your guitar however you're most comfortable with it and however sounds best to you.
It's all a question of personal preference. I know plenty of people who like to stick to standard because they don't like the sound of dropped or open tunings (Durero takes it one step further and tunes the whole guitar in fourths to make it as systematic as possible), but I really like the way a switching tunings forces you to looks at the fretboard in a new way and possible come up with something you wouldn't have thought of otherwise. Just tune your guitar however you're most comfortable with it and however sounds best to you.