That candle thing is a nice idea. Doesn't Yankee Candle(or one of the other candle companies)have a Baby Powder scent? That would be cute too!
I've been to both kinds of showers...snacks and dinners. Either are very nice, and the snacks don't have to be elaborate.I was just at a luncheon one where they had ham and brie sandwiches on this cute little rye bread, graham crackers with a cool whip/vanilla pudding/sour cream spread with fruit on top(kind of like s'mores, but with fruit), and fancy salad with those fields greens, and a nice vinaigrette dressing, and a cake for the dessert. They servied lemonade, iced tea, and punch. It was fairly simple, but very nice, and quite elegant even though it was simple.
The pad and paper for someone to write down the gifts is always a good idea, because invariably the card gets separated from the gift, no matter how hard you try to keep them together.
I've also been at ones where they do a baby wishing well. You have a little basket, some people go so far as to make or rent a little wishing well, and have everyone bring a small thing to use for a baby(ie-nail clippers, socket covers, little socks, a pacifier, travel-size baby lotion or powder for the diaper bag).
Another nice idea is getting little index type cards with a baby theme on them(or you can make your own using stickers etc)and having each person write down a piece of advice regarding raising children. Later, it can be put together into a scrapbook, along with pictures from the shower, for a nice rememberance.
Good luck. It's nice for you to do this, even though somewhere deep down it's probably kind of hard, based on your own issues. Having had fertility problems myself, I know it's difficult to go to baby showers. Your friend will appreciate your effort, and the amount of love you're showing by doing this.