You will definately need at least 1 static ip for what you want, otherwise the SSL wont work. Also what David has said is very true with regards to speed and contingency, after all whats going to happen when either the line dies, or the power cuts? the answer is a downed server, loss of trade and your customers loose confidence (especially if your offering email addresses).
Again, echoing what David has said - colocate with a provider (there are enough on this forum that will probably PM you anyway offering some service), its fairly inexepensive and you get peace of mind and the flexibility to easily run SSL, your email.etc
Just renember that cheapest provider isnt allways the best provider
