IMO you should choose a plan with at least 5 Gb. bandwidth (more recommanded). My board is relatively small (600 members, 25 MB DB) and my site's monthly bandwidth consumption is around 5 Gb altough I disabled all IMG tags, attachments and converted all buttons to text links in my vbulletin.
What I didnt like about Web Host you referred is they are hosting their own pages in ASP.

This can sometimes point: They have expertise in NT hosting more, dont know PHP good, their PHP support is bad etc. I personally dont count on hosts featuring ASP in their own pages when it comes to PHP.. This is not a general rule but a hint I regard while comparing different hosts.. My 2 cents..