I got my 2001 GT-S with every option minus the gold emblems and carbon fiber dash for $17,900. I personally have no problems buying used cars, especially when they are only one year old. I don't think you're an "idiot" to consider buying a Celica, they are much nicer looking cars in my opinion. As for the RSX having more ponies, yes it does, but it is also a bit heavier. Find two equally good drivers and sit one in an RSX and the other is a GT-S, they will post times very close to eachother, with no one car always being faster then the other on every race. Their engines are extremely similar to one another. You have a point on the interior though. It's not that I think the Celica interior is poor (in fact I really enjoy it, nice wrap-a-round feel to it), its just that the RSX looks more like a luxery automobile inside. One thing I will say, however, is that I feel the body style on the Celica is much more appealing then the look of the RSX. The RSX looks kinda Civic-ey with some different headlights, this I find waters down its sporty performance stigma.
Please don't take this as a RSX bashing, as you read (hopefully) I hold the RSX in high regard, almost to the same level as the Celica. I am just letting you know what made me choose the way I did in hopes that it will help you make a better decision.
One car I will semi-bash is the WRX though. I don't care how fast it is, it really is an ugly automobile, both inside and out.