How long are you going to be there? Are you looking for something you can get at a discount 65-70% ARV?
I bought a townhouse for $515k in Dublin 2006. It went down to $375k. I had to wait it out for 10 years but I sold it for $650 recently. If you are going to hold on to it even in a downturn and buy it for a good price you should be ok.
Timman Kumar, both Pleasanton and West Livermore (where I am from and live) are great areas. Given that, first and foremost I would ask yourself how long are you going to live there. This is important if you will be having kids going through the school system. Where you buy will place your kids in to different schools.
Appreciation wise, Pleasanton has always cost more than Livermore and in that case saw a similar percentage drop in price during a recession and a similar percentage rise in appreciation recently. Since one area cost more than the other, it could be said that Pleasanton appreciated more dollar wise as a whole, but similar priced homes increased about the same amount. Both areas will rebound at a similar pace to each other.
As per your "How much over list price" question. Livermore currently has 26 SFR on the market and Pleasanton has 34 SFR with quite a few of those being in Ruby Hills. As for duplex, triplex, and quads, they are nonexistent in each market. That being said, properties that are priced competitively and are coming on the market now are often getting multiple offers all above market price and some homes going for more than 10% over list. It isn't unheard of to see 10+ offers on one house.
You'll definitely get more bang for buck in Livermore. Likely more relative 'upside' in Livermore as well going forward, as Pleasanton is getting very pricey and has very limited inventory.
To echo @Tyler Johnson's comments, Pleasanton only has 3 detached homes priced under $1M currently; whereas Livermore has 15. The schools on the west side of Livermore are VERY good.
To illustrate that further, I showed one of my rental properties in Pleasanton last night (near Shadow Cliffs), and one prospective tenant couldn't get her kids into Joe Mitchel Elementary (Livermore, which has an IB program), so she wants to move to Pleasanton.
Another general question. I have heard about crawl space and concrete slab foundations. For the first time I came across Brick Foundation in west livermore. Online research showed that some banks may not even give loan for brick foundation and it is not safe. Have you guys heard about brick foundation, any ideas?