Hello there young skipper!
Well everything depends on your style of gameplay and your needs
I would suggest keeping it pretty easy and simple starting with the major mega mods out there:
GFO=Game Fixes Only.
It's pretty self explanatory right? It's a ''mega mod'' but it fixes only the ton of bugs in the stock game, very good and easy to install
LINK:
http://www.subsim.com/radioroom/showthread.php?t=151796
TMO=Trigger Maru Overhauled.
It's a very well done mod, it's easy to install and gives you a very different experience, you really should read more about it in the release tread
LINK:
http://www.subsim.com/radioroom/showthread.php?t=132330
RFB=Real Fleet Boat.
It's the main oppositor to TMO, it's more focused on making the game as realistic as possible while TMO is more focused on making the game challenging
LINK:
http://www.subsim.com/radioroom/showthread.php?t=159709
FOTRS=Fall of the Risingf Sun.
It is a very amusing mod, it makes a lot of changes in the visual side of things, we usually define it an ''eye candy'' mod beacuse it's pretty to see, very pretty indeed.
It adds a ton of new ships, makes visual changes but the main game is based on TMO.
LINK:
http://www.subsim.com/radioroom/showthread.php?t=147988
RSRD=Run Silent Run Deep (The Campaign).
It's a very very good mod to go with either TMO or RFB and GFO as well I believe.
It changes all the campaing layers and it adds realistic convoys routes with actual Dates and task forces wich tooks those paths during WWII.
LINK:
http://www.subsim.com/radioroom/showthread.php?t=123467
this are the ''major mods'' in my opinion but there is as well
Optical Targeting Correction which modifies the scopes and other things and
The travellers mod for TMO wich I never tried.
OTC:
http://www.subsim.com/radioroom/showthread.php?t=181172
Travellers mod:
http://www.subsim.com/radioroom/down...o=file&id=4106
Hope this was clear enough
Cload