So I completed the game last night :-)
Trying to decide what to do next.
A) Buy another game
B) Play DD again as a different character in a different style.
I'm tending towards buying another game, Fallout 2 or Sacred Gold comes to mind - so if I go that route, any suggestions?
TIA

If you played Fallout 1 and liked it then Fallout 2 is a sure bet, even if you never played the first one FO2 is pretty good on its own if you like post-apocalyptic games .
Sacred Gold is a different matter. Do you like games that play like Diablo 2? If yes, then Sacred Gold might work for you, otherwise get something else.
I played Sacred Gold for a while, but got tired of the never ending re-spawning. Imagine clearing out a whole section of the map, stepping just one screen away to sell your loot in town and then finding out that the area you cleared is crawling with enemies again in the same gaming session. Sure, you get lots of experience and loot, but after awhile you begin to get annoyed at the never ending enemies even when you are in town in the middle of a conversation. I suppose I will have to eventually get back to it, but I will need to buy an extra large supply of Patience pills.

If you liked the DD game play than I would say Sacred Gold. It has a couple of broken quests but does not have any of the problems we experienced with DD.
The re-spawning can be tedious but I used it to level up quickly. The story doesn't pull you in like DD but the huge world allows you to enter and exit the main quest at will. It could take months to finish if you just put in 2 or 3 hrs a week, let me know how that works out for you . . . =^ ) There are several other great RPG's available on GOG . . . for me, until the DD patch . . . it's already installed so . . .
I finished DD as well but I am waiting on the patch before I play it again.

I did like DD - a lot :-)
And Fallout 1 for that matter too
Thus, perhaps, the quandary

Decisions, decisions. Fallout 1 and DD are two different styles of RPGs, you have played both so . . . you know which you prefer.
DD is not an option for me since I really want to wait on the patch before playing again, finished Fallout, so it is SG for me, some of my reasons are:
As Urthgris pointed out, SG is a lot like Diablo but . . . I liked it better for single player. . . larger world, non-linear, save any time, compass/current quest selection, five weapon slots, dual wielding, five combo skills, the A key option, multiplayer, "cool" characters, minimal bugs, etc. etc.. I always felt that Diablo abandoned the single player mode in favor of the online play. SG is what Diablo single player could have been (IMHO). SG is designed in sections, each one offering more difficult enemies. The respawn was tedious until I learned to use it to my advantage . . . which was for leveling up before moving to the next section. After a certain level, the enemies in a section seem to ignore you, when that happens you are more than ready to move to the next section. Took me 91 hrs to complete both campaigns and I discovered slightly more than 40% of the world. I didn't see 60% of the game?? I gotta go back, this time as a Battlemage. . . =^ ) The dragons were the only unbalanced aspect for me, really hard to kill early on.
Since you have already played Fallout 1 then it would be a natural progression to play Fallout 2. I suggest you visit Killap's site http://www.killap.net/fallout2/web/About.html and consider his patch and his restoration project, click Download at the top of the page. I have not used either with the GOG version but they should work, maybe visit the Fallout forums for a confirmation. Start another DD, try Fallout 2, try SG . . . decisions, decisions . . . =^ )
Edit: Well, for whatever reason, I failed to mention Beyond Divinity. I have it but have not played it. Wanted to wait for a full play thru of DD with the patch. That would be the obvious next game if you liked DD, the reviews have been disappointing though.

Yep, that pretty much describes where I am at.
I think I am going to go for Sacred Gold, putting Fallout 2 on the back burner for now.
Thanks for all the recommendations and thoughts, it sounds that either will be good games to play.

One other SG tip, being "Diablo trained", I ignored the other characters combat arts items till well into the game. In SG, you can use other characters combat arts items to enhance your own weapons and armor.
Started keeping them in my stash along with amulets and rings, all of which can be inserted into weapons and armor. ( You can also change the inserted items but you forfeit all but the one you drag back to inventory ) A nice perk I thought . . . =^ )

Go for FO2 in my opinion. I bought it about 10 years ago and it had me hooked for ages. As soon as I completed it I immediately restarted with a new character with different stats, just to see the other endings I could get. You've not completed the game until you've started again with an evil child killing character who is continually hunted by bounty hunters. Even now, 10 years on, I play the game again once every year or two to soak up the atmosphere of being a near loner in an apocalyptic world.
DD is fun for a while, but I don't think it has the depth of the Fallout games to warrant several repeat plays. There's always more to discover in Fallout, but from my experience of DD so far, the plots are very linear and there's very few opportunities to stray from the chosen path. I think in the long run you'll get more from playing the FO games as opposed to DD.

I ended up regretting that I've bought Sacred Gold. It's not that great.

For anybody that is interested I went with Sacred Gold - probably give Fallout 2 a shot next :-)

Looking forward to hearing you impression of SG