Yep, I've been playing for a couple of months and have racked up ~150 hours in it, I find it completely addicting as well!
I've mainly got Map mods, because I'm more interested in the exploring bit than the actual trucks. Here are the mods I have on at the moment, or ones I have previously used.
ProMods - The first mod I used, creates new towns in Europe (including Croydon and Portsmouth in the UK), and a whole new map for France and Scandinavia (all of Denmark, and a lot of Sweden/Norway/Finland). Also fixes a lot of the dud signs in UK and Western Europe, which is nice. Also note that you have to create an account for this one, but it's quick and worth it.
Realistic Lighting - Definitely worth it, makes the nights longer (10pm to 4am nights all the time is quite unrelalistic), and the sunsets/sunrises are really pretty. Goes with all the other mods I have which is useful.
Trucksim - Map 5.3.1 - An absolutely HUGE map that I'm currently exploring. You have to have the Going East DLC for this (worth the purchase IMO), and it adds on Slovenia/Croatia/Albania, as well as a little bit of Denmark, Southern Italy, loads of France and the entirety of Spain/Portugal. In addition to this, it even gives you Northern Africa; Morocco/Algeria/Libya/Egypt. Definitely worth a check out. This cannot be used with ProMods, because of the overlap on Denmark.
RusMap 1.4.7 - A map for Russia (as well as a couple of towns in Belarus), which is pretty neat. This can be used in conjunction with either ProMods or TruckSim 5.3.1 above, which gives you a massive map.
Those are all the mods I have. You'll need WinZip to access them.
Some of the mods will install for you (your EuroTruckSim directory the folder called 'Euro Truck Simulator 2' in your documents. If you unzip it, and there are some ".scs" files, then copy them and paste them into "My Documents -> Euro Truck Simulator 2 -> mod". Activate them by selecting "edit profile" on the start screen and ticking them from there. It should be noted that it will significantly increase the initial loading time, and makes my laptop freeze for about 30 seconds on the first load.
My only other tip to enjoying the game is not to take it too seriously!
Hope this all helps, let me know if you need any help with it, it took me a while to work it out, it's confusing at first.