If you want to stay away from antibiotic anything (soaps/creams/etc) as some shops recommend, you could just use regular mild liquid soap (softsoap is great...many body washes that aren't overly perfumed work too) and/or products such as Ear Care, which are antiseptic solutions sold mainly for the care of pierced ears, but can work on other piercings as well. Warm salt-water soaks can be beneficial as well.
As a side note (and preventative measure), make sure that the shop you're going to is qualified to do good piercings..you can often ask to see a portfolio of photos of other piercings somebody has done. Just because you're "only" getting a navel piercing doesn't mean you should have to deal with substandard work. A clean shop and a skilled piercer will help your healing immensely, as well as give you someone to call if you aren't sure about how your piercing is healing.
Ohyeah...as far as tribal tatts go, defref...I've seen many tribals (and barbed wires) that are obviously people trying to follow a trend, but I've also seen many tribals/other "trendy" tattoos that have been beautiful expressions of self-identity. Tribal shouldn't automatically say "sheep" because many of the designs were made specifically for one person and may have a much deeper meaning than you can see at first glance. Yes, they're overdone in many areas, but that shouldn't devalue a person who gets their tribal art for personal reasons (ethnic identity, a hidden design, a piece of artwork they drew for themselves, etc).
[edit]Personally, I have a celtic-styled tattoo that I created the art for myself and that incorporates "Ladi" hidden on the inside of my arm. I'm chinese, but irish culture has interested me for most of my life, and I happen to like the eternal-cord type of symbolism most celtic knots have. Irishness may be a trendy "thing," but that doesn't mean it influenced what I chose to have put on my body. And yes, my next tattoo (and possibly the one after that) will be tribally influenced, as well as incorporate celtic knot elements. The one after that will be almost entirely tribal. Sense a trend?

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~Ladi