Anticipating MySql space needs??

[FrankC29]

I'll be opening up a forum soon, a general discussion forum for my city. I'm going to run vBulletin pretty much stock. I'm trying to figure out if the host I currently have the domain at provides enough space for MySql, assuming my advertising methods work and the site gains a good following. I figure it's better to make a change now if I need to, rather than when I have a big ole database to move around. Anyway the numbers:

The web provider is HostSave

1000GB disk space, 100GB traffic, 100mb MySql. The disk space and the bandwidth seem more than adequate, actually I'm kinda impressed, for $8.95/mo anyway. The 100mb MySql seems wimpy though, at least from the searching I've done in these matters. For another 4 bucks a month, I can double all these numbers, which will give me more disk space and bandwidth than I could ever possibly use, but will 200mb MySql be sufficient? How big a board do you think this could indeffinately suport? How about attachments and avatars, I hear they are no longer stored in the db but now reside in regular space? If a change is needed, I suppose now is the time. I'm eyeballing Xpera, but any other web host suggestions are appreciated as well. Thanks.