[ i would stay away from the extremely cheap ones like hi-point unless you are only carrying them for home or self defense ]
Why would you want a "cheap" pistol to use for the protection of you and your loved ones? IMHO, home or self defense requires the absolutely most reliable, accurate pistol one can manage. Not saying you need an Ed Brown Custom at over 4K, but you'd be much better served by avoiding the "cheaper variety" Ask yourself, "would I trust my life with this Hi-Point?"
To the original post, it all depends on what feels good to you, that should be priority. I'd rather have a super accurate, comfortable weapon in a .22 rather than a .45 that O couldn't shoot or operate worth a darn. That last point was extreme, but you get the idea, shot placement is key. All in all, it depends what your going to do with the weapon, is it a carry peice, target, range gun, hunting, camp gun????? From what it sounds like, you might want to look into a .40, near .45acp performance, but high capacity like the 9mm. If it's only a range gun, go with 9mm, ammo is waaaaay cheap, but also, lots of great perfomance 9mm ammo is out there, so you wouldn't be undergunned, really this is an endless topic, but it all boils down to personal preference and the weapons intended use/uses.