It depends on your intended output device. Is this for viewing on a computer? A TV? If the latter, what kind (PAL, NTSC, 1080, 720P, etc.). As a general rule, framerates range from 24 - 60 frames per second. Any of these will produce good results.
That would be accurate if you choose a 45 fps frame rate, but I don't know why you would choose that particular rate. If you don't have a particular output device in mind I would probably choose 24 fps as it will cut down on render time and it's easily convertible to other formats if you should choose to do so.