2million has a post on starting to plan for his wedding - there are a lot of interesting comments about how much is "enough" to spend on a great wedding ("perfect" weddings don't exist in reality, and planning for them costs a fortune).
I put in my two cents worth on how to plan an affordable wedding that still provides priceless memories (and not too much stress for everyone):
As my wife's parent were both deceased, I (and my parents) paid for our wedding. We did it "on the cheap", but it was still very nice - and I used the money we saved to splurge on a "round the world, New York , London and Paris (with QEII from NY to the UK)" honeymoon ;)
We spent a few enjoyable weekends driving around Sydney looking for a church with the right "atmosphere", did up our own wedding invitations using some nice paper, an inkjet printer and a sketch of the church the minister gave us. The biggest saving was to do the reception as an "afternoon tea" at my parent's house, which was possible because we only invited very best friends and our relatives (we don't have many living here in Australia anyhow), so we only had around 30 guests. We also got a couple of standard cakes with suitable icing from a local bakery and staked them up to construct a wedding cake - "real" wedding cakes cost a fortune and are practically inedible. It looks fantastic on the wedding photos.
We also got several of the relatives to take photos, videos etc. and got copies of everything. Unless you're planning on sending your footage to "funniest home videos" you don't need a "professional" photographer (most are pretty average anyhow).
The wife borrowed her wedding dress from one of her best friends, and my sister made up a veil and other bits and pieces which made nice keepsakes . (You intend to keep the dress and the wedding cake forever? Sounds like "Great Expectations")
Anyhow, you should discuss this option with your fiancee (doing a "home made" wedding rather than the "crass, commercialised" version) and see what she says. You never know till you ask.