There are 3 default ships to choose from - Ferox, Nemesis and Phobos. Each handles a little differently and have different fire power.
Personally I enjoy Nemesis ship the most due to its fire-power and multi-direction shooting but Phobos probably the most powerful in terms of fire power but slower.
Anyway you have to finish the game with all three so play on Rookie difficulty and see which you prefer to then tackle the hard difficulties and see what takes your fancy.