yes the beyerdynamic range is quite good, the 770 pro with an amp is kick arse, but thats really serious money.
personally i think you will be severly dissapointed in the hp890's. my dad bought a pair for $120aus and while they are probably great for his classical i really prefer my ksc-35's. the koss just have way more bass, just the right amount for me, while the hp890's have err, not enough for me at least.
if you would be plugging the hp890's into a source that had some sort of equaliser so you could increase the bass (not megabass that still sucks even with the non existent bass of the hp890's), then the hp890's might not be too bad. i just prefer the bass heavyness of the cheap koss's and i think most other people would too. the hp890s are pretty good for games, as from my experience you can tell where the sound is coming from pretty well, although again i still like to increase the bass response which i can from my soundcard.
if you want something that does have some decent bass, then some models in the beyerdynamic range are very good (not the dt831 and 931 apparently). some of the models in this range have nice impactful bass if thats what you want. To get them in australia i think the easiest way is to contact snufkin either on these forums or the overclockers australia forums (
http://forums.overclockers.com.au) and also this site
http://www.cashncarry.com.au/ sells most of the beyer range at not bad prices.
either way i really recomend you talk to snufkin you want exactly the kinda advice snufkin can give you. either the DT250/250, DT531, DT770Pro/250 and DT990Pro and possibly the dt250/80 are pretty good options if you can afford them
the hardest part is deciding between them
. note some of them do need amps, such as the 770pro, whereas for others its recomended but not essential. if they are a little out of your budget i know someone who even chose the dt231 over the hp890's after listening to them both. unfortunately i think you missed out of the overclockers australia ksc-35 group buy which is pretty good(but not as good as the expensive beyers) for the $75 aus price IMO.
edit: without listening to any except the 990pro quite a while ago when i no idea about headphones, which i liked but cant remember any more than that, i think the dt531 for use without an amp or the 770 pros with a headphone amp ( = bye bye $$$) seems to have gotten the most praise.