My favorites are those that sound like they were written by people I'd actually sit down and have a cuppa with in real life, rather than "literary" sounding stories. The best memoirs combine the honesty of a journal with the gravitational pull of a great novel.
I've always hoped to one day have an adventure worthy of retelling this way--I talk about my day to day nonsense all the time on the Internet, and have told a few true stories that might not be out of place in a memoir, but still, up until recently I haven't really thought that anything that interesting would ever happen to me.
Now I'm beginning to think it just might. I'm thinking of travel and adventure as things that do happen to "people like me" (meaning broke-ass fat girls too shy to order their own pizza), if I gird my loins and make them happen. What these memoirs show me is that anyone can live an extraordinary life if they remain open to the possibility that something new and wonderful could be around the next corner.
Here are my favorites, in no particular order; they include single-author memoirs as well as collections of true tales:
Eat, Pray, Love by Elizabeth Gilbert
The Amazing Adventures of DietGirl by Shauna Reid
Expecting Adam by Martha Beck
Book of Shadows by Phyllis Curott
Holy Cow: an Indian Adventure by Sarah MacDonald
I'm the One that I Want by Margaret Cho
Such a Pretty Fat: One Narcissist's Quest to Discover if Her Life Makes Her Ass Look Big, or Why Pie is Not the Answer by Jen Lancaster
Fun Home: a Family Tragiocomic by Alison Bechdel
No Touch Monkey! and Other Travel Lessons Learned too Late by Ayun Halliday
The May Queen: Women on Life, Love, Work, & Pulling it All Together in Your 30s, edited by Andrea N. Richesin
Sand in My Bra and Other Misadventures: Funny Women Write from the Road, edited by Jennifer L. Leo
Got one to recommend? Do so in comments!