Consider the following:
1. Person was a USA dual status resident as of end of Dec 30, 2008 (resident alien for just 1 day, Dec 31, 2008 per Substantial Presence Test)
2. As of today (Feb 20, 2009) this SINGLE person (still in the US) is eligible to "make first year choice" since he/she meets the two conditions (31 days in a row in 2008 AND 75% presence rule). Note, this person is SINGLE.

Question. What is the advantage of making the "first year choice" in this case (more specifically is there any benefit related to the standard deduction ?)

Can a person claim the standard deduction ($5450 for 2008) ? What confuses me is that really you are a "dual-status" resident choosing to be treated as a "resident alien"... but tax rules (chapter 6 of publication 519, topic "Restrictions for dual status tax payers, point #1) clearly state that dual status residents are NOT eligible to claim the standard deduction on the 1040.

If one cannot claim std. deduction, is the possible advantage just to file a simpler return (only one 1040 instead of 1040 + 1040NR as a dual status) ?

I've seen some posts on this forum, advising people to claim standard deduction when "making the first year choice as a SINGLE person", but I don't understand on what basis.

Any help/explanation would be awesome. Thanks.

You do not meet the criteria for filing under First Year Choice to file dual-status because you did not have at least 31 consecutive days in resident status. Further, to file as a resident alien, you must be married.

BOTTOM LINE: You are a non-resident alien and should file as such, filing Form 1040NR-EZ plus Form 8843 if you were under a F-1 or J-1 visa in 2008.