This is more a philosophy question than a question about specific baits.

just wondering how you guys choose a different bait for a different situation. i mostly use trial and error. honestly if im fishing topwater i usually use a sammy or spook jr, and may try a popper but dont expand too much. sometimes if the water is stained i will go with something louder than a sammy but that is almost always my first choice.

anyhow does anyone have a better system

I will often choose a bait because I just feel like fishing a particular lure.  Sometimes it works, sometimes it don't.

Then there are the times when I calculate water clarity, water temp, cloud cover, depth, structure, cover, wind, and season.  Sometimes it works, sometimes it don't.  

if there is a good amount of wind, i'll throw the buzzbait first.  If the wind dies a little, so there is just a little ripple on the surface, i'll usually throw a jitterbug or a skitter walk.  if it's dead calm, i like a spit'n king or a Rapala original minnow twitched on the surface.

Jason

I like a redfin for early mornings, usually they'll always come up and hit one of those if there on top that day.... over deep brush I like a spook or a chug bug...

If there's a little ripple, I like to start with a buzzbait.  If it's dead calm, a Pop-R or some type of chugger, or something I can walk the dog with.  If it's fairly choppy, out comes the Devil's Horse.

All of the above are true... It really depends on several factors.

If you know (perhaps by using different sub-surface lures before) that bass are in an active state, throw them a fast, noisy lure - buzzbait, jitterbug etc. If you know they are inactive, throw a slower, less noisy, scaled-down in size lure which will accomodate the water conditions (still or rippled surface, water clarity).

Early in the morning I let water conditions dictate how I start. If it is smooth and calm, I will use a popper and vary the twitching speed until I find what they prefer. If it is a bit windy and the surface is rippled, I will walk the dog - any of of my "dogs" (sammy, zara, superspook, skitterwalk). If I see a lot of activity I may switch to a buzzbait as well... But keep in mind there are exceptions - sometimes poppers work with windy conditions and "dogs" work in calm - so you really have to experiment a bit...  

Heavy Cover

Buzzbait for wood

Soft or hollow frog for floating vegetation

Open Water (flats, etc.)

Walking bait in clear water

Popper in stained water

Target (laydowns, pockets in vegetation, etc.)

Floating minnow if calm and clear

Popper if calm and stained

Prop bait if windy

As always, these are guidelines only and your mileage may vary.