I've 2 bikes from 98 and one of them is a Trek (of the carbon Y frame variety) and it's had generally a positive reception on this site - the other is a canadian made steel hardtail that I've yet to post a picy of on here yet as it has a baby seat on the back of it and I just can't bring myself to photograph it like that!
I think '98 was the first year Trek made welded aluminium frames after many years of selling bonded aluminum bikes. Not much changed in the look of these bikes for a few years afterwards... until they started using hydroformed tubes (?) in the last couple of years. Maybe that is why it looks so 'modern' because you put it next to a '04 bike and not much has changed, where as you put my '98 Trek next to the suspension bikes Trek was making in '04 and mine looks 'retro'.... well it does to me anyway.
I have noticed a bit of brand bias on this site... anything startling with 'K' seems to get the juices bubbling!