there are various ways to differentiate packages. you can do it based on hours of coverage, number of shooters, whether any products are included (beyond the CD, assuming you are providing one), whether a free engagement session is included.
so the base package might be one shooter for 4 hours whereas another package would be two shooters, 6 hours and a book/album plus free engagement session.
some people limit the number of images but for me it's always a pain to choose which ones so i'd rather just give them all of the ones that turned out. people are pretty good at sifting through images these days.
these guys play up the fact that they can help plan and coordinate as well as photograph:
http://continuumweddings.com (you can request a free PDF with planning tips)
i don't know if it matters in this scenario but seems like everyone wants a deal. so we jack up the price and then offer a discount to satisfy them.
i've had a lot of people ask about how many images they will get (we don't limit the number the way some do). i think the groom might be doing the math and thinking about how much they are spending per image. probably not the best way to evaluate a wedding photographer but it's something people are used to at the supermarket when they compare cost per ounce.
All my quotes for weddings are base on the following items and fairly detailed that way if there is argument later it is all clearly quoted.
Time spent at the wedding per hour estimate hours (don't be an ass if it takes 1 hour longer)
2nd,3rd shooter, assistants, drivers,....
Special gear if any, props (this is for things I would not take for the usual wedding. I had a client request a 12 by 7ft special backdrop so the friends could take fun pictures in a special setting.
Make sure you include somewhere the cost of post processing (don't make it a dedicated line) take your hourly shooting dates and factor in post-processing.
Include a special line edits requested by the client at x$ per hour.
Offer options such as albums, gifts,... Or what ever they may fancy. Keep this open for after the wedding.
All my quotes specify that the client will get at least 100 professional pictures(except if there are some extreme circumstances) I usually deliver between 400 and 800 pictures but not all with full edits just good looking.
Make it easy for them to exclude certain items if they want to save costs.
No one has mentioned bridal portraits. A big deal with most brides who also want a print to display at the wedding. Your best bet is to look at several wedding photographers in your area to get an idea of pricing.
As stated, most packages vary not only by hours but by products, so knowing your product costs is important.
The best advice given so far is to realize that post production is by far your greatest time investment, so don't cheat yourself. If you have never shot a wedding before, I would also suggest hiring a second with experience which can be another major expense to incorporate into a package.