Both options have thier advantages. I've got the AWD drive train, but for me that was a viable option as I live in Winnipeg, where we drive on ice and snow 7 months of the year.
The AWD drive train is amazing on ice and snow, add 'good' snow tires (I've got Nokian Hakkapelliitas) and you pretty much have a ice monster. There were days last winter where I got to work and everyone was complaining about how slippery it was, yet I'd drove in at ten kilometers over the limit without so much as noticing.
That being said I'd probably go with the manual 5-spd if I could do it again. The problem is that rule of thumb is that when you take the same engine and put an Automatic transmission on it you loose a fair amount of the power in the Automatic drive train. Add the AWD drive train and it sucks even more of that horsepower. The AWD really is a dog on power in comparison to the 5-spd.
If you live in a Winter climate or more importantly a mountainous Winter climate the AWD is definately worth consideration. But if you don't see alot of snow, then go with the FWD. Every Winter I'm thankful I got the AWD, but every spring I'm kicking myself wishing I'd gone with the 5spd.
My recommendation. Get the 5spd. With the money you save have your dealership work in a set of stealies with 'good' Winter rubber. And yes there is good and bad Winter rubber.
I agree with all the comments above. Here is some more info from my take on it...I test drove a 5 speed when the Aerio first came out in 2002 with the smaller engine and only 140 or so HP, but I bought the 2004 with AWD with the larger engine and more HP. Based on my expereince, the bump in power on the new engine somewhat compensates for the parastic power loss from the auto and AWD systems. That being said I am sure the 5 sp with the new engine is obviously more potent.
On a side note, for a light car with over 150 HP, I must admit that the power is less spectacular than I thought it would be for "class leading". The torque peaks low which is good so you don't have to wind the engine up like a Civic, but either the gearing ratios, the auto box, and/or AWD do sap some power out. Still it is a pleasure to drive and a rocket ship compared to my Cavalier...
Another factor to consdier is the type of driving you do. With a lot of stop and go rush hour gridlock I really appreciate the auto box. Thats my 2 cents...
I love my AWD allthough I just wished Suzuki made it available with the 5 speed manual gearbox. I know a lot of Aerio owners who would trade their ride in if it became available. Personally I have the 03 with the 145 HP and find it is powerfull enough for me. But then again I have only raced a couple of Hondas in the 1.25 years I have had the car and beat them both. I have been driving 4 wheel drives since my 1963 Land Rover so for me there was no other choise.