Making good use of SQL 2005/2008 Rank() function

Ran into the age old problem of migrating data from one system into a new system  where new system requires a unique row id but the previous system does not.  In the scerario,  I am moving 400,000 records across a linked server from SQL 2000 to SQL 2005/2008.  Generating a rowID per row is expense in any type of cursor or While Loop for 1/2 million records.  Using the 2005/2008 Rank() function I managed to migrate 400,000 records in under 3 minutes with the linked server connection running over internet through my home cable modem connection.  Not too bad at all.

SELECT rank() OVER (ORDER BY fPat.PatientID, fMrn.MRN) as RowID

FROM [FRIS].FRIS_DB.[dbo].tbPatients fPat                 

INNER JOIN MRIS.[dbo].W_PATIENT mPat ON mPat.Pat_Id = fPat.PatientID

INNER JOIN [FRIS].FRIS_DB.[dbo].tbMRN fMrn ON fMrn.PatientID = fPat.PatientID