My question to you is, "Can you justify spending the money to buy a software so that you can take care of noise in your photos?"
CS2 isn't exactly cheap, retail you are looking at spending at least $1200. Unless you have the means and extra money lying around to purchase the software, then by all means go ahead and get it. I'm not going to get into the details and advantages of using CS2 but it is a definite step-up.
Let's say you own and drive Honda, you are contented with the car, it does what you need it to do, getting you from point A to B, but you would love to get a Porsche, because it is nicer to look at and is alot faster. But at the end of the day, you still use it to get you from point A to B, maybe just alittle faster. IF you have the money to make and justify such a purchase, then go ahead and buy it.
Sorry for being so long windered, but the point I am trying to make, why spend the money on something you think is a "nice to have" rather than something that you "need". Yeah I would love to drive and own a Porsche, but I don't need such a car. And I think neither do you.
That's just my $0.02.