What's the best chainsaw on the market?
I'm in the market for a chainsaw but really don't know much about them. I will uses it often sometimes all day long. I never know what kind of tree I'm using it on or how big or small the trees will be. I want to buy something that will last for years despite all the constant use. My budget is 1500.
What chainsaw should I look into purchasing? What characteristics should I look for? Where can I purchase them?

I would go to Sears and ask for help. They are super helpful. Heck, you might even find a lumberjack to help you. I would also purchase it with a credit card to get some protection/extended warranty just in case what you end up buying is a piece of junk. Amex has a great protection plan — FREE –for big ticket items.
Good luck!!
Stihl or husqvarna are top brands and probably the only ones where you’ll be able to spend that much money. I wouldn’t go to sears, as they won’t have what you’re looking for. I’d go to either a local lawn-mower type shop or online to Stihl or Husqvarna and find a local dealer. Go in and hold them see how they feel. My work has several larger saws and we buy Stihls. Our 20" saws are MS 260′s which retail will be around $600 I think (we pay wholesale prices). An MS 360 we use with our 24" bars and they’ll be a couple hundred more. Our MS 660 we use on our 32" & 36" bars and will be around the price you’re looking to spend, but they’re awfully heavy if you’re not cutting that large of stuff. We also have one MS 880 that holds our 4 and 5 foot bars but is really heavy and will retail over 2K.
ARL, when I went searching for a chainsaw nearly 6 years ago I was advised to; (1) find a decent and reputable brand, (2) understand that if it were heavy to hold in the shop then it was going to be even heavier after a few hours sawing, and (3) the longest bar was not always the best – they can often become unwieldy if too big. I opted for a 20" bar because it offered the most versatility when it came to wood widths.