I spent a lot of time researching how many calories to eat during the day... My suggestion (which worked well for me during the last year) is to put in how many calories that you would need to maintain your goal weight (there are many websites that can give you a target if you google it). Then use that as your basis... My thought process is that when I actually get to or near my goal, I wont' have to make any changes or go 'off' my diet. When I had more to lose, I would increase the deficit by a few hundred calories a day to try to speed up the process a little but all in all I have found that I eat far more calories then I expected too and still have lost weight. I have settled into about 2100-2300 calories a day (I workout a lot) and am still managing to lose little by little.
Hope this helps.
May 10, 2011 - Starting weight - 341 (Rock Bottom)
June 12, 2012 - current weight - 188
July 4th, Near term Goal 10 - 180
April 6th - Near term Goal 9 - 199 (Met!)
February 18th - Near term Goal 8 - 210 (Met! March 9)
January 12th - Near term Goal 7 - 225 (Met! Jan 5)
November 12 - Near term Goal 6 - 245 (Met! - Nov 9th)
Total Lost: 153 Lbs