I really came on to this to mention that Christ was not created, but saw that got covered...then read Thorne's posts... skipped to the end to see how things ended. Largely, Christmas is a "bigger" celebration for 3 reasons.
1) It marks the end of the liturgical calendar, a New Year's of sorts. The church year is sort of like a mini-replay of the life of Christ every year.
2) Everyone agrees on the date of Christmas celebration. Easter is based on the lunar calendar and the Eastern Orthodox Christians, Coptic Christians, and Western Christians are often a little bit different on the date of Easter.
3) Mostly though, the secular world grasped heavily onto Christmas traditions and celebrations. Not that Christ's birth isn't a huge deal, it certainly is. At my church though, we spend basically the entire week at church. (short services monday, tuesday, wednesday, Maundy Thursday Mass + Footwashing, Good Friday is a...long service, then on Saturday we have Easter vigil which is about 3 hours and a wonderful amazing incredible service of anticipation and fulfillment. Then sunday morning is Easter worship service He is Risen indeed!)