RE: My personal deadlift hell!
Technique for deadlifts is a bitch, especially as there are two distinct styles ('conventional' and 'sumo'), both of which are viable means of shifting ridiculous amounts of weight, so people who use one technique will have trouble if they employ the advice of people who use the other...
Re: Leaning back at the top of the rep. I dunno if you can injure yourself doing it, but as it seems somewhat pointless (once the weight's up, it's up) so there's not much point in risking it.
Re: Other hints for deadlifting technique - I found this site useful.
Really, really useful if you can be bothered to read through all of it...