Aluminum or Glass
I just went through the anal retentive process of evaluating boats before I bought one. The selection process goes like this...
Glass, Aluminum, or Wood -- Wood is too high maintenance for most people, especially me. The main advantage of a glass boat was that it is slippery so it slid over rocks. Most aluminum boat manufacturers now offer a UHMW sheet on the bottom of the aluminum boat that makes it almost as slippery as glass. Because of that I got a Hyde 14'6" low profile aluminum with UHMW. I got a decked out boat with storage seats, galvanized trailer, etc. Hyde factory store is in Michigan if I need parts or service. Love the boat so far. Have run it in rivers between 200 and 4000 CFS. Handles 1 to 4 people, but 4 is pushing it. It rows very easy, but can be stern heavy if you run a motor. I run a 4hp Yamaha four stroke and wish I had gotten a lighter motor. 4hp is more than enough for me. I rarely use it anyway.
Round chine or square -- The chine of a boat is the corner where the side meets the bottom. Some are rounded, some are square, some are raised, and some are proprietary (willie). As all of the manufacturer websites say... Round chines don't track well. What does that mean? If you're pulling plugs all day, you'll stroke the oars more often to keep the boat straight. However, my guide on the Deschutes this year wished he had a round chine boat because the strong currents tend to grab the chine and spin the boat. In other words there are advantages to each. There are also techniques that can be applied to each. In other words, you don't row a square chine boat the same way you row a rounded chine. In my opinion, the chine design is mainly marketing hype. Aluminum boat manufacturers preach the benefits of square chines because that's how they're built. Glass boat manufacturers preach the benefits of round chines because that's how they're built. (except hyde's glass boats also have a square chine so they preach only raised chines -- whatever)
Length (and width) -- Assuming weight is a constant (which it ain't), the longer and wider the boat is, the less water it drafts. So get the longest and widest boat without getting too heavy. Shallower drafting boats also row easier and are more stable. Not to mention they have more room. I chose the 14'6" length because it is considerably lighter than the 16'er and my freinds aren't too heavy. Also important to note that the Hyde 14'6" has the same footprint in the water as the Hyde 16'. In other words, teh 14'6" rides higher in the water than the 16' because its lighter yet has the same displacement.
Highside vs Lowside -- Midwest fishermen can get by with a low profile. The highside only offers disadvanteges in the midwest. Wind, weight, hard to get in, etc. I met a guy out west this fall who ran 5 people in his Hyde aluminum low profile. He also ran class 4 rapids in it. (not with 4 dudes!)
Options -- Dry storage is nice, but rubbermaid tubs work well too and can fit in and around the seats where the dry storage goes. That way when you don't need dry storage, its not in the way. Rubbermaids are also hundreds of dollars cheaper. Storage alone in my boat ran about $700. I bought the deep storage front bench seat and 3 lid storage rowers seat. The rower's seat rocks! I'm not completely sold on the front seat yet. I maybe would have been better off with the pedestal since most trips don't require that much dry storage. Anyway, if you want to save some money, do it on storage. Galvanized trailer is a must in midwest because of road salt. (so my friends tell me) A cover is unnecessary if the boat is aluminum. Get the best oars you can. I got the counterbalanced cataracts. They're nice. So are Sawyer Lightweights, but they're wood and require refinishing every few years. If you do get wood oars, get tip protectors.
Be sure to read the thing on TSS classifieds by "email@example.com" regarding "don't buy a drift boat until you read this". He gives some good information that anyone buying any drift boat should know. He's also a nice guy. I bought my boat from him.
Also try some general searches on the following forum... piscatorialpursuits.com. Try searching on hyde, lavro, clacka, willie, fish-rite, driftboat, drift boat, oars, row, etc. People really love Lavros and Willies. I almost bought a Lavro.