I just started kayaking but i've already been in many rivers and lakes in the area and hidden several paddle-to geocaches (yes, i'm bringing those stupid things up again!)
i know everybody's saying not to get an inflatable, but that's exactly what i did and i really like it. of course, i can't make performance comparisons with a hardshell cause i have no experience with one, but in my advanced elements inflatable i can keep a pace of 2-3mph upstream and 4-6mph downstream, which i don't think is all that bad. i started out with a $60 coleman inflatable from walmart to make sure i liked kayaking. that lasted a few trips, but on my way from the recycled bridge down to a cache at one of the islands in atsion lake, it popped and started to deflate. i paddled like mad to a nearby takeout and had to hike it back on a trail. the boat actually didn't get punctured by anything-a seam on the seat just burst under the pressure of my weight! needless to say, if you go inflatable avoid the colemans.
the advanced elements advancedframe has been an entirely different story. i got a great deal on it for only $250 for an '05 model (an '06 model is $380 and doesn't seem to be any different based on the packaging) at rei. i did have a problem with a leak in one of the risers after a few weeks of heavy use, but i took it right back to rei and they're shipping another one. i think that problem may have had more to do with me putting all of my weight on the risers when getting out than any defect with the boat itself. other than that, this boat sets up quick and performs superbly. it has aluminum frames in the bow and stern that supposedly really help performance. the air chambers are inside of a tough skin made up of rubber on the bottom of the boat and canvas on top, so even if you happened to get a puncture or leak (unlikely as it's very tough), you still have the air chambers intact keeping you afloat. the advancedframe is about 10.5 feet, which seems to be the perfect size for narrow piney rivers (try doing the upper mullica between jackson road and goshen with something longer!). they also make a convertible 1 or 2 person version of the boat that's longer and lets you move seats around to accomodate your trip. the convertible isn't on clearance on the rei website, but i was at the marlton rei store 2 days ago and they still had one of them left on clearance there.
my reasons for getting an inflatable over a hardshell were basically storage/transport concerns. i have a little crv with no roofrack or anything and i didn't wanna be messing around with trying to mount stuff up there. also, i'll be able to take the boat with me to school next year and just store it in its duffel bag in the back of my car, ready to yank it out, blow it up, and take a paddle at a moment's notice. how many other dorm-dwellers can say they brought an 11foot kayak with them?
an infatable is great if you need to save space, and the other nice thing about it is always having it with you. you don't need to go to the trouble of mounting a 60 pound hunk of plastic on your roof everytime you want to go boating...with the advancedframe, i'm able to happen upon a river or lake and just go paddle for a bit on a whim, and that feels really good.
so far i haven't found anyone else to paddle with so all my trips have been solo. after the first time i went out and almost couldn't make it back upstream past a strainer i realized about always going upstream first and coming downstream for the return trip. also, if you're looking for places to paddle i've found some great lakes, rivers, and put-in spots simply from studying google earth imagery. the only downside is google earth can't tell you if a lake is private :-p
if you're into that wretched geocaching game be sure to check out my paddle-to caches; they don't get nearly as much traffic so it's exciting when somebody finally visits one. my name on gc.com is electricheadx.
link for advancedframe clearance
my advancedframe on lake pachoango
malaga lake cache page (somegreat wildlife photos on here that i shot from my kayak)
They are clumsy to paddle and not comfortable for long trips, IME. 
