What follows is a traditional division of nuptial expenses. However, because we no longer live in a society wherein tradition is paramount, this is intended as merely a guide. The question of who pays for what these days in effect comes down to who is both willing and able to. Remember - communicate with all the involved parties at the outset of planning and be both realistic and courteous.
Invitations, and other wedding stationery, including postage.
Bride's dress and all accessories.
Bridesmaid's dresses/outfits.
Flower arrangements for the reception.
Entire reception - food (caterer), drink, hire of venue.
Photographer's fees.
Music for the ceremony - i.e. choir, organist and/ or soloist fees.
Transportation for bridal party to ceremony and reception.
Aisle carpets and/or canopy, and any additional decorating costs .
Wedding cake.
Flowers for the church.
All extras such as confetti.
Announcement of wedding in press, although this is sometimes done by bride's father.
Bride's engagement and wedding rings.
All "personal" flowers - includes the bride's bouquet, bridesmaid's flowers, mother's corsages and boutonnieres for all men in wedding party.
Gifts for best man and ushers.
Fees of church/chapel etc. or civil ceremony as well as the fee for clergy or judge.
Groom's suit and best man's, if rented.
Transport for him and his immediate family to the ceremony.
Wedding gift for Bride.
Accommodation for the wedding night.
Honeymoon.
Marriage license.
Wedding gift for Groom.
Wedding ring for Groom.
Gifts for attendants, although this is often paid for by groom.)
Going away outfit.
Wedding gifts for the newly-weds.
In this day and age, quite often the groom's parents do contribute to the cost of the proceedings, usually by covering the cost of the drinks at the reception.
You can do this by assigning each thing an actual amount (i.e., $750 for your gown, $200 for the attendants gifts), OR by assigning them percentages of your budget. For example, while you may be prepared to spend 30% of your budget on good food and wine, you may only want to put 5% towards wedding favors. By putting percentages on the different elements of your wedding, it helps you put things in perspective, as it is very easy to lose sight of the big picture.