Tank Brands, etc

I am addicted to my CFB's so much I want to get them into a bigger tank. I currently have a 10 gallon tank that seems to be a little crowded now that I have 3 CFB and 3 guppies. (Yes, I know Guppies in the tank are a bad idea, but I am willing to risk it ). I want to get something larger so that I can do more with the tank. I am looking at getting a 20 or 30 gallon tank, however the questions I have:

Good brands?
Where to buy? retail or online? what stores?
What is a good price for a 20 gallon? 30 gallon?
Can I still use my Fluval 1plus in the tank or should I get a larger pump/filter? (I am only going to have about 10 gallons of water in either)
How "dense" do FBN's like the water/land to be?
Is there a "rule of thumb" for how many CFB's can live in a tank together? (ex. 1 per 5 gallons?)
What kind of lighting do I need for live plants? (anything other than the standard floresent lighting)

If you could just answer these in #'d responses that would be great.

Online's no good, shipping's usually outrageous. Go to your local pet shop. I've found that All-Glass aquariums (that's a brand name) tend to run cheaper than most others. Their 20 gals run about $25-35, depending on store markup.

No idea about the fluval, have no experience with them.

If your animals spend most of their time in the water, then make the tank mostly water. If they like land, use more land. I wouldn't do any more than 1 per 5 gallons, but more experienced keepers will surely chime in.

If you want live plants, go with low light plants such as hornwort, java moss, java fern, and elodea (anarcharis(sp.)), as then you don't need additional lighting, which may stress your newts.

I would HIGHLY recommend removing the guppies. You're the one responsible for keeping these newts together. How would you feel if you were in a tank and someone decided to house you with a bear, just because they were willing to risk it?

I think that filter would still be fine. One firebelly per 5 gallons sounds about right. I'm not sure what you mean by how "dense" the water/land should be.

If you aren't in a hurry, read your local newspaper classified ads and go to yard sales - used aquariums occasionally turn up. You didn't ask, but... I'd suggest getting a screen lid instead of a hood. The water will stay cooler. If you can find a hinged one, you can still put a flourescent light on top of it.

I've kept guppies with newts in the past. The main problem is when the temperature drops in winter. It's wonderful for the newts, but the guppies become inactive and tend to die. Personally, I wouldn't deprive the newts of their cool period in order to keep guppies happy.

Ya i just have the guppies in there to give the newts something to look @ and chase

Guppy babies are excellent food for CFB's
In the wild CFB's eat chinese minnow babies. Minnows love cold water, so maybe we should switch to minnows in the tank hehehe.

However, minnows tend to be fin nippers, so not too sure what they would do to the newts in an enclosed space. I haven't put my minnows in the same tank as the newts yet, but may be an interesting experiment to do.