For my daugter's first birthday, we decided to have it at a really nice park (it is a summer birthday) and had it catered by Sonny Bryan's barbecue and everything. It was a cold rainy windy day. Turned out it was the last day of rain before a 2 month+ long drought that summer. Wouldn't you know it? Most of the people came, but my daughter got soooo sick we had to cut it short. I wish we hadn't gone to all the trouble because she definitely doesn't remember it and it ended up being so miserable, that's all anyone remembers about it when we talk to people who were there. The food was great, the cake was great and the kids that came had lots of fun at the park when the rain would slow down enough for them to play, but if we were to say "Remember our daughter's first birthday?", the response is usually "Oh my gosh, yes, that was miserable...". That's so hard to hear when you're thinking of memories of your little kiddos.
When my son turned one, we decided just to have a birthday party at home with snacks and cake and invited all friends and family. It turned out my son got sick that week and all our friends with kids decided not to come because everyone was trying to get their kids over the same virus my son had come down with. It was a bit of a hassle calling everyone at the last minute to tell them the birthday boy was sick, but better that than having our friends mad at us for not telling them and getting their kids sick as well. All our family came, which was nice, and because it was just family, there was no need for a big "to do". We did get some cute pictures of our son with his cake and the balloons we bought. But all the streamers and other decorations we purchased are still in the bag we bought them in since we never used them.
Moral of the story, the first birthday, as most everyone has already mentioned, should be the least hassle for the parents it can be. The child won't remember it and there are so many things that could go wrong, it's really not worth putting too much effort into it when the little one won't even know what's going on. That's my opinion thru our past experiences anyway. :-)
Good luck!