One of my best games ever! Yes I did play the USA, but it was tough nonetheless. The game started as an effort by me to keep under Infamy and be nice, however it developed into a sort of world conquest after I accidentally went over my infamy limit fighting UK and Mexico in the 1860s, so I just went with it.
I fought two containment wars with France, then beat up a whole lot of minors, uncivs and secondary powers before fighting big wars with Russia, France, UK and NGF after 1900. I could of done better in conquest, especially by fighting my wars with the GPs earlier than the 1900s on and using my DPs better. However I learned a lot for future games. At the end I had reduced the UK and NGF to less than 20 brigades (after the peace). Needed a few more wars to "clean-up" the map a bit, but ran out of time. Oh I was responsible for the large Greece, I figured that supporting their expansionist aspirations worked for me as well.
Final Infamy was 1636.17. Final number of states was 158. I got literacy up to 77.6% despite all my African and Asian states I added. I had more money than I knew what to do with and had a 117 million pound surplus bank, with an income of 49.57 thousand per day surplus at the end. In my final big war with the UK I called up over 1k brigades of reservists and had over 2800 brigades but was still in the green during most of the war. I finally ended up with 3261 active brigades and 3171 ships, with about a third of those dreadnaughts. FYI, I ended at peace so I wouldn't have inflated numbers from being at war.
Some other screens below for your reference:
http://img840.imageshack.us/img840/802/productionscreenusagame.jpg
Notice that I produce everything!
http://img834.imageshack.us/img834/830/populationscreenusagame.jpg
Notice the preponderance of Buddhists and Chinese in the empire.
http://img847.imageshack.us/img847/2829/nationalrankingsusagame.jpg
http://img607.imageshack.us/img607/3558/nationalcomparisonusaga.jpg
http://img153.imageshack.us/img153/451/countrypopulationusagam.jpg
http://img171.imageshack.us/img171/6199/budgetscreenusagame1121.jpg
All in all this game represented the best and the worst of the game. If you actually just go out of character and go on a conquest rampage intelligently you can really bust out. Note also for this game that I didn't reload from errors, use any cheats or really game the system (beyond standard combat tactics). The game was vanilla played with the latest 1.4 beta download.
It was really fun!!!