Buy whatever you like. Some things that I have noticed. Production division has overtaken standard in popularity for most of the matches that I have been in. The most popular pistols are Glocks, CZ and variants.
You can use your inglis hi power for you black badge, but I would not use it for competition. When I started I did not have an RPAL just a POL, and the only pistol I owned was a colt 1911 A1. I used it for the first few years and I really liked it. However I ended up changing the sights, the beavertail the mag well, the trigger, the mag release, just about everything. In the end I dropped about 500 modifying the gun and it is worth far less than if it was untouched.