Thank you all for your replies, much appreciated !
Had a look at it and looks like a fun game, added it to my wishlist for a later date.
Skyrim is the clear choice for me given your requirements. Mod it to hell as well with better textures and you're away for a good time!
Actually have that one installed already (with 3 DLC's) since others told me it is a stunning game with mod's, but once I looked at all the mod's I got totally lost and it never went anywhere. Now though had a look at the Skyrim thread here at OcUK and saw the mods suggested by ThaReaperGuy in the first post so might have a go with that when I have a day off next time.

Look at the supplied screen shoots it do look interesting. =)
Having a good time with Dragon Age : Inquisitor but I would wait for the xmas sales as it's Origin.
Thanks, only tried SimCity 2013 at Origin (the trial version so part from that, never played Origin games) but will try and keep this one in mind later on.
Skyrim + mods
Dragon Age + Mass Effect, 1,2+3
Fallout 3 + mods
Injustice Gods Among Us
Magicka
Skyrim and Dragon Age will have the magic covered and content/story line. It took me a few tries to get into Skyrim, and I liked DA2 so maybe I'm strange. Skyrim with mods and DA3(not played DA3) will have the pretty covered.
Mass Effect has no magic unless you consider biotic. Yes it's a shooter, but doesn't really feel like one i.e. CSGO BF3/4 etc. I loved the Mass Effect story, the ending of 3 was meh though.
Fallout 3 has lots of content, again guns but I don't consider it a shooter really. Especially if you use the VATS system. Like Skyrim it took me a few tries to actually get into the game
Injustice I liked for the story. Yes it's short and there's not much to it, and it's a fighting game at the end of the day but I enjoyed seeing superman turn evil.....
Magicka definitely has the magic covered, very funny game great with friends.
PS Have you looked at Anno?
As above, will look into Skyrim later. =)
Magica will look into, saw it loads of DLC's to it though.
Will look into the others and see if they peek my interest, never know. =)
Since you like 4X games have a look at Endless Legend ; gorgeous visuals and UI, the gameplay isn't half bad either !
That one is on my Wishlist already so might grab it if it shows up during the Christmas Sales.
Slightly similar, but I'd recommend Sins of a Solar empire: Rebellion.
Amazing strategy, and can be very tactical securing planets and managing a fleet, defenses and resources.
Tried Sin of Solar ages ago, wasn't really my thing but thanks for the suggestion.
As mentioned Skyrim. its great when modded.
Guides on how to mod:
https://www.youtube.com/playlist?list=PLE7DlYarj-DcLS9LyjEqOJwFUQIIQewcK
https://www.youtube.com/playlist?list=PLE7DlYarj-DdhDG41roBVJfNCqvO5MmKP
The 2nd playlist is for Nexus Mod manager, don't use that. Use Mod Organiser from the first playlist. I've just linked it since it mentions some Mods you should use.
And when you get your head around all that, but a EMB on it
Thanks for the YouTube guides, will have a look at both later.

.. And yes I gather it take a while before getting my head around Skyrim, considering all mods available, but what does EMB stands for ?

(Probably something really simple.. lol )
Thank you again for all replies, will keep me busy the next time I have a couple days off from work. =)