Thinking of my first tank!

[justinl]

clowns can host just about anything, powerheads, coral (of all kinds), etc etc. there was some talk that wild caught ones would more readily host stuff, but it wasnt proven. something you can do that might help is find a picture of a clown hosting whatever you want your clown to host (example: if you wanted the nem, youd find a pic with a clown hostign a nem) and leave it by the tank.

i would discourage an anemone... there are plenty of other better options. a toadstool leather for example makes a great clown host.

as for the rock, it is virtually impossible to say how much is needed in weight. it is much more dependent on the volume the rock takes up and how you stack it. in fact the only really reliable tool for that purpose is your own two eyeballs. you'll just have to wing it. look at some other reef tanks and decide roughly how full youd want your tank to be and just go by that. i agree with digital that the best way to go about it is to get a bunch of nice rocks of differring size/shape. it makes aquascaping easier and more flexible.

and if i were you i would stick to at most four of those fish... like 1 clown, 1 panda and two chromis for example.

do you know that you really want a panda goby? you would need at least one colony of any pocillopora coral. be aware that these arent easy ish to keep... certainly not anywhere near beginner level. they also lay their eggs on the underside of sps coral which can harm the coral if it isnt a large colony. and to top it all off the pandas sometimes nip sps polyps. just making sure you know what you're getting into.