the generation 4, and 3 - i never played a generation 3 game but most of the 'new' ones i encountered, new being post 2nd gen pokemon - were a bit poor in design generally, i thought; just boring or garish or whatever; there were some promising ones who had stupid looking evolutions IMO, like snover and bronzor, and even chimchar's final evolution was disappointing, looking like a bad clown, even though he's a fantastic starter otherwise; almost all the other ones i've encountered so far have been somewhat underwhelming.
the exceptions i've seen so far are lucario and luxray; both are awesome, for obvious reasons - shinx, luxio and luxray are all awesome, predatory electric cats, win, and lucario is smart, looks cool, and is extremely strong in the game as well, which was a pleasant surprise! i had thought they were related due to the names as well before i encountered lucario but fortunately they aren't.
there are others, too - the LEGENDARIES in generation 4 are amazing, as far as i'm concerned! dialga is one of my all time favourites, great backstory, looks absolutely fantastic and has great moves, type combination and powerful stats; the elves are cool, giratina looks menacing with a great type combination, and cresselia looks fricking fantastic too, can't wait to get them. even heatran looks decent, and i'm gutted i can't get darkrai or arceus, even though arceus is IMO the single most ridiculous pokemon ever, the one which made me step back and think 'ok... that was stupid' i mean, come on, an alpha omega pokemon? seriously? other then its problematic back story, it does look and sound like possibly the single most powerful and fun pokemon as well, to be fair. shyamin is the only one that doesn't interest me that much; he's no sonic.
for all my complaining though, many aspects of diamond are better then any other generation i've played, and it seems to be a more balanced experience in the field then white, as well; whatever. lucario, luxray and the legendaries FTW