A droppable item w/ 41% haste is very nice. I think 41% is the most haste of any droppable item, however I wouldn't buy one at the price this usually sells for now that Gates of Discord is out. The tribute effect "Swift Arms" works exactly like worn item haste. It has 5 "tiers" that are 20%, 25%, 30%, 35% and 40% haste. These are avalable at levels 20, 30, 40, 50 and 60.
So at level 60 you can basically "rent" a 40% haste item. You could rent the tier 5 haste for hundreds of hours and not have spent anything near the amount you would have paid to buy this item. Not to mention, at some point during those hundreds of hours of high-end playtime you will certainly come accross a 41% or better No-Drop Haste item. Some of the new GoD high level haste items have worn haste as high as 46%.
I guess this only makes sense if you have so much PP you don't know what to do with it and you buy this item for a pre-level 60 alt. But even then, there are many many 36% haste items for 40-70k (Cowl of Mortality, etc.). So at 300k you'd be paying a quarter of a million plat more just for an extra 5% haste.