With the outstanding response from the community on the pre-release of 1.8 (you have downloaded it, haven't you?), we've set up a special page on the wiki where the bugs you find should be reported. This will give Mojang a specific all-inclusive place to look and fix them.
The Infinite item bug is anoying, where if an item drops from you exiting the workbench, it becomes an infinite item when you pick it up. Also after abusing this glitch (Survival)
My minecraft seems to be crashing very often.