Underdog Saws
Overbuilt saws
For their weight, these are often shunned by the stopwatch crowd. These saws will run for a long, long time. Most folks running them could not tell the difference between these and their more powerful brothers.
Stihl 650 - A great, strong saw that can often be had for considerably less than a 660. Put a $40 dual port muffler on it, and you're probably running neck and neck with a stock 660. Stock to stock, I couldn't tell a difference between them both with a 32" bar in big wood.
Husky 365/362XP - I just love the 362XP. Less than a pound difference between that and a 357XP, and it just rips...it feels noticably stronger than a 357XP or MS361. Plus both the 365 and 362XP can be found used or NOS for loads less than a 372XP/W. When you wear it out, it's easy to upgrade to OEM 75cc or a BB.
Older saws
Husky 346XP OE - Yeah, the NE is more powerful and is better in bigger wood, but it is also heavier and often comes with a cat muffler which needs to be replaced. If you can find a nice OE used or NOS, grab it! It IS handier than the NE, and revs like crazy without the need for porting and/or new/modified mufflers. I have both and find myself reaching for the OE more often, or going to a bigger saw.
Husky 350 - So they are not pro saws... They run great, and are often ridiculously cheap on the used market. So, if you lend it to Uncle Al, and he runs straight gas through it and blows it up, no big deal. Pull the good parts off of it and buy another one on CL for $100, and run the crap out of it.