My specialization is hi load projects. With me you can be sure that I will build project that can be scalable for hi loading.
My primary focus is backend development Symfony 2 + Amazon AWS on nGinx; PHP, Symfony, Git, Ajax
I use memcache and memcached, as well as I can do own dedicated caches into applications that use a lot of data.
As DB - MySQL (good experience in sharding, partition, replication), NoSQL - MongoDb or Cassandra.
Using of APC (alternative