If I have your income amounts correct - assuming your 2009 total income including the severance would be $202,000 ($100,000 + $102,000) then your federal income taxes would be approximately $48,717. Without the severance in 2009 then your 2009 taxes would be about $19,102.
If the severance was paid in 2010 and your other income was $28,000 for a total of $130,000 then the taxes in 2010 would be about $27,500. If the severance was paid this year then your taxes in 2010 based on $28,000 would be about $2,380.
So if these assumptions are correct and the severance was paid in 2010, then you would save approximately $4,495 in taxes ($51,097 - $46,602) - [(taxes on severance in 2009 would be $48,717 + $2,380 = $51,097) and (severance in 2010 would be $19,102 + $27,500 = $46,602). However, if you obtain employment in 2010 and make signficantly more than the tax differences change.
Also, when you receive the severance pay may affect your unemployment compensation benefits so you may want to contact the TX Workforce Commission.