For those asking about the forum:

1. It is currently hosted on a dedicated 8GB 2GHz quad-core Xeon server from softlayer.com (server location: Dallas, TX USA)
2. Backup (daily): on same server (with RAID 5). Offsite: NAS from softlayer.com (NAS location: Washington, DC USA)
3. Forum disk space size: ~12GB
4. Monthly bandwidth: ~450GB
5. Number of emails sent per week (mostly from forum reply notification): ~8000

I personally own the vBulletin license, so a new vBulletin license is required (~$195).

For those asking, yes a lot of the forum systems (including open source ones) have vB migration tools. Sure, a cheaper or free forum system can be used but think about the expertise of the volunteer who intend to administer it (both the front and back end). Think about daily backup, DDoS attacks, automated spammer attacks, etc. The admnistrator(s) should be able to perform/monitor/avoid these 24 hrs/day.

There is also the task of creating custom plug-ins. As an example, TMO has a custom plug-in that links with the Maemo.org membership database so karma can be computed correctly off the members' TMO posts/thanks. Not all forum systems have the 'Thanks' featue, so think about how that can be supported and the thanks data migrated.

If moving to a new domain/forum name, I agree that members should be notified and asked for their permission.