top 5 commercial brews...
 

1. Black Butte Porter- from the source- Deschutes Brewery in Bend, OR- on nitro
2. Guinness from the tap
3. Anchor Steam
4. Session Black
5. PBR- the perfect lawnmower beer...

thoughts?

First thought is: you need to get out more. :D Just kidding. Each of us will have our own list. Mine would have to include Arrogant Bastard or Slap Your Mammie on tap somehow...... But to each their own.

Depends on the premise of the question. Am I stuck on an island surrounded by salt water for the rest of my life with an unlimited supply of 5 beers? Or is it the 5 best beers I've ever had, knowing I might not want to consume them in quantity?

Mine would be
Victory
Allagash
Lagunitas
Deshutes
Spaten

The order would change a bit from time to time, but I think I could live the rest of my days happy a tornado in a trailer park on that line up..

Cheers
Jay

these are my picks

Rodenbach Grand Cru
Kostritzer Schwarzbier
New Glarus Moon Man
Orval
Bam Noire from Jolly Pumpkin

I'd have a real hard time picking a top five without taking style into account. I'll just pick the best from some of my favorite styles instead:

Barleywine: Founders Boltcutter

IPA: Olde Hickory Death By Hops

IIPA: Bells Hopslam

Brown Ale: Lonerider Sweet Josie

Imperial Stout: Founders Imperial

Smoked: Aecht Schlenkerla Rauchbier Marzen

1. Three Floyds - Arctic Panzer Wolf and Zombiedust (it's a tie)
2. Bell's - Oberon
3. Surly - Furious
4. Stone - Ruination
5. Bell's - Two Hearted

Just short of the list:
Highland -Gaelic Ale and Cold Mountain, Bell's Hopslam, Magic Hat #9, Sweetwater 420

For mowing the lawn and yardwork.....Old Style

I'm going to count only universally findable product since you said commercial..
Orval
North Coast Old Rasputin
Oskar Blue's Dale's Pale Ale
Great Divide Titan
Rodenbach Grand Cru
And if there were 6 I would add Anchor Steam
If I went rarer I would have to think a lot longer..I'd almost call this my top 5 go-to-commercial craft list-Beers I could typically find in any good bottle shop in most states

1. natural light
2. coors light
3. miller 64
4. sharps
5. o'douls

just kidding... someone said I needed to get out more- maybe true- top 5 just isn't fair but what the hell- here is 5 more- not neccessarily in any order

Pyramid Wheaten IPA
Redhook ECS No Equal
Bert Grant's Imperial Stout
Michelob Dry
Elk Head Extra