I have used Wyeast 2124 a lot in the past before my then LHBS closed. The LHBS I have been using for the past 6 yrs or so carried WL and some Omega. Never really got into dealing with huge starters for liquid yeasts and Lagers so I most often used dried strains. Now my current and only LHBS around is closing...so it's dry yeast from here on out by mail order only. I'm ok with that, dry yeast has done just as well for me when treated correctly and I'm not that sensitive to any differences over the liquid strains.
Not much different than what is already posted,
34/70...pretty well balanced, good for a lot of styles middle of the road Lager yeast.
S-189...I like this for biggger Lagers. O-Fest, Bock, Helles...but would probably be great for any Lager.
Diamond...Have only used it a couple times, but seems to be somewhere in the middle of 34/70 and S-189 but leans more similar to S-189. Bigger mouthfeel, yet attenuated and crisp, clears well.
S-23...I took a gamble with this on my last batch and brewed a Kentucky Common Ale with it, so fermented closer lower 60's and it came out great. I don't know if I trusts it enough to use for a true Lager, but I want to experiment...maybe on a 2nd runnings beer or something where I won't be out a whole batch if I don't like it. I think it might have it's place though.
My favorite, hmm...If I had to pick one it might be S-189/Diamond tie but they all have a different place.