I was always under the impression that doing research in a well paying country was beneficial because the research points add to your score in that country. Thus I always placed my first base in US (also covering Canada). My next 2 bases are in Asia and Europe. Initially radar posts, then interception, then fully fledged all rounders. My research is usually carried out at one base, but redundancy is built into other bases. Each fully fledged bases has some manufacturing capability for personal armour and the like, but one base has a high manufacturing capability to build ships. More bases are located in Southern hemisphere: South America, Africa, Australia (usually interception only but guarrisoned all the same). Then there's a storage base when stuff begins to pile up. And one final strike base.