Thanks for the comments everyone. It has always been my dream to have a big tank, ever since I was a kid. I've had aquariums since I was very young (but parents wouldn't let me get a snake).
The filtration is underneath the tank - gravity fed from one end into filter wool, through bioballs, into a settling sump and pumped back into the other end. As simple as that.
I have a lot of different fish - plecos (my favourite), corydoras, flying fox, bristlenose, cynadontis sp?, different types of gouramis, black widows, tiger barbs, clown loaches, all the different 'sharks' (red fin, red tail and albinos of both), platys, swordtails, guppies and I've had the smaller tetras but something's eating them. I got rid of my huge angels because they used to round them up, but something's still getting them.
The schooling fish look the best, especially when I have fifty neons swimming together.
Rebbellybite, part of the cost goes to the bedroom and office behind it since it's their walls. The acrylic was going to cost nearly $10 000 if I wanted it in one full piece (had to come from overseas) so instead I went for two pieces (that's why there's a black strip down the middle - $7000 cheaper). All the black border is actually stainless steel. One piece had to come from Melbourne and another from Brisbane.
All worth it though.