Happy New Year !
This will be the year of SharePoint 2010.
Having spent a few days migrating MOSS 2007 sites to SharePoint 2010. I am impressed the ease at which this can be done - as long as you follow a few basic rules.
1. Make sure that your code, site definitions, webtemp files and other required artefacts are deployed (hopefully using a WSP file) BEFORE you migrate any content.
2. Use the powershell script cmdlet Mount-SPContentDatabase to migrate your content database(s) from MOSS 2007 to SP 2010. This gives a running % of how far it has got. Better than the old ststadm command addcontentdatabase which told you very little.
3. Just in case do an IISRESET /noforce.
4. Navigate to your new site and wait a few seconds and your new site come up.
5. Add in the new SP 2010 ribbon as described in :_
6. Test the new site - alot.
There you have it.