I've read a lot of books and tried different things when my daughter was a baby 4 years ago and none of them worked until my friend recommended me the book "Heathy Sleep Habits Happy Child" (see link from amazon) and of course with some tips and helps of my friend who went through a crazy time (no shower, no tooth brushing, not even washed her face and she is the type that she has to put make-up on even when she just needs to step out to dump garbage) with her 1st child.  The trick for my daughter (and my friend's daughters and a few friends we helped) is ROUTINE & an EARLY bedtime. I highly recommend this book from Dr. Marc Weissbluth as it teaches other sleep strategies when kids grow older and start fighting against sleep.  Anyway, my daughter slept well since then.  So to answer the question of when do babies sleep through the night, it properly won't happen until almost 1 year old (with 3 naps) according to Dr. Weissbluth.

http://www.amazon.ca/Healthy-Sleep-Habits-Happy-Child/dp/0345486455/ref=sr_1_2?ie=UTF8&s=books&qid=1272393767&sr=1-2

I can totally relate to your sleep training.  A great book is Happy Baby, Healthy Sleep Habits.  My 2 1/2 year old always required a great deal of "effort" to put to sleep.  It got to the point where we had to lay with her for an hour, sing a bunch of songs, tell her stories....etc...then she would get out of bed 3 or 4 times a night to come sleep with us.  We finally had to do something when we found out our 3rd baby was on the way (baby #2 sleeps like a dream). 

I completely agree that the cry it out method is no good - for younger babies though.  Your daughter is old enough to know that she more she kicks up a fuss/stays active, the more Mommy comes in to get me.  A great method that worked for us (obviously every baby is different though and this does not work for everyone) was to thoroughly explain the "rules" of bedtime and to have a routine that you DO NOT stray from.  For example, we do bath, 2 story books, a story we make up from our head, then one last song, hugs and kisses and then we left the room.  You can leave the door open and stay close by so that when she gets out of bed, you pick her up and just say "bedtime baby/sweetie/whatever" and that is all.  Don't interact with her or start a conversation or anything and don't go in and check her, let her come out to you.  Yes she cried at first, but that is how she's telling you she doesn't like the change - she is not hurt or scared or sad.  If she poops, change her diaper quietly in dim light and don't interact with her.  I promise you she'll learn that after the end of the routine is her bedtime.

Sleep independence is very important and you don't want to be going crazy.  Most importantly though is be consistent, she won't learn if you're trying everything all the time.  GOOD LUCK!!!!

Regarding sleep issues, I've been to hell and back. My 18 month old started waking up repeatedly throughout the night, sometimes staying awake for 3 hours!!! I was so sure she suffered from insomnia! We were at our wit's end and didn't know how to stop her from waking up. Of course, we struggled to keep her lying down in her crib, but she would just stand up and cry nonstop until you picked her up. Even by trying to rock her to sleep, as soon as I lay her down back in the crib she'd wake up in 5 minutes. After about 2 monthts of sheer exhaustion and failed "sleep training" I decided to make a bed of pillows on the floor beside her crib and lay down with her. This way at least I could be lying down and not have to carry her around for hours. Suprisingly she fell asleep beside me and didn't wake up for the whole night. We tried this method for 3 days and she continued to sleep through the night on the bed of pillows. At this point I realized that the issue was simply that she didn't like her crib because the mattress was too hard. I needed to test out my hypotheses. So I bought a foam mattress pad and cut it out to fit the mattress size. Now her crib is cozy and soft and she's sleeping through the night! Voila!!! Just a simple adjustment like that saved our sanity and we're all sleeping better.

Since our daughter is old enough to sleep in any position she wants, having a soft bed is not a suffocation hazard as it may be for younger babies, so just be careful. She doesn't sleep with blankets, and the foam pad is under the bedsheet, so there's no risk of getting tangled.

Good luck!