Must be something you are doing wrong or have done to it. Don't see that on my original iPhone. Each new OS has made it faster.
Essentially you are talking rubbish.
I see. Because you're not experiencing it, it's rubbish?
I have the exact same issue. From the time I upgraded to 3.0, my original iPhone is so slow, it's ridiculous. I'm suspecting (and this is just a guess) that background spotlight indexing is the culprit - a feature I wish I could disable as I never use it.
Sometimes, the phone is so slow that I literally miss calls. The screen lights up with the swipe to answer, I swipe and I swipe and I swipe and the phone appears to be frozen. Then, right at the last second, it answers, but the screen doesn't update and by then the call is sent to voicemail. I've even had situations where the phone never rings at all, but I get a new voicemail notification.
During the rollout keynote of the iPhone, I was in the audience. I remember Steve saying the killer app on a phone should be the ability to use it as a phone. Ok, so why does it take 5-10 seconds to open the "phone" app and make a call after 3.0? Coincidentally,

, the 3GS was released about that time and the buzz was speed speed speed. I can't help but wonder if either 1) making higher demands on existing hardware or 2) not optimizing newer software for older hardware is actually part of Apple's strategy to get us to buy newer equipment. I'm just waiting for the day that my 8 core Mac Pro suddenly feels slow after an OS update.