I'd get the penguin 170 thats what I have on my 30...just because it has the bio-wheel...the 10 gallon we have is also from walmart and we replaced the filter form that kit with a penguin mini
GT3050 what city are you in? Check http://www.caoac.on.ca/clubs/clubs.html for aquarium clubs in your area, someone will no doubt have a used tank for sale. I know there is plenty of pickings in the Ottawa area.