You've got a solid little gun there. It should handle most commercial ammo, but any gun will take a little 'break in' time (to allow the various surfaces of the mechanism to 'wear into' each other) - shoot 200 or so rounds of FMJ/target ammo through it, then for self defense, try various JHP brands to see what it (and you) handle the best. Beyond that, try the search feature of this board for more opinions/thoughts.
These guns are pretty good straight from the factory. However, if you find that you do not like the sights (some do and some don't) then check out some of the posts in the "gunsmithing" section about replacing them with the Wilson Combat three dot set. I did and I am very happy with the results.
I would start out by shooting basic WWB solid point ammo, then after you feel comfortable with the gun, start shooting some defence rounds and see which ones the gun shoots best. My PT145 does very well with Speer Gold Dot for short barrels.
BTW, welcome to the forum. Are you the same fellow that recently posted over at the firingline, or the high road (can't remember which it was...)?
The MilPro series of pistols has an outstanding plus... there is very little you will want to "hang on" these guns. No high dollar grips, do-hickies, or thing-a-majigs!
It lets you spend your money on a good holster... do some reading and looking... asking opinions, but making up your own mind for your own needs and then buy something worth the money (I've got several cheap holsters that will never been used... can't sell them in a gragage sale because my wife would know how many I've bought!)
Then with the rest of the money you've saved... go shooting! There is no better single investment in your new gun than time spent practicing to make you into the shooter you want to be!
One of the reasons that the PT1911 isn't getting the respect it deserves is that a lot of 1911 shooters have a check list of putting those enhancements on their guns and are frustrated that it comes with it already. Of course they pay $600 for their gun... put $300 worth of trinkets (upgrades) on it... and then offer to sell it for $550 so they can buy another gun?
Enjoy your PT145, I do. I have been using CCI Blazer Brass I got from Wally World, best prices around when they have it in stock, it sells out real fast. I use Hornady Tap +P 200gr for carry, it likes that also. The Heinie sights are great now that I got use to them.