I'm not a salesperson; if you need more reasons to convince yourself to spend money, just wait a bit longer. The moment you are ready to get into PC gaming, you can buy the best/ best value parts and enjoy your expenditures fully.
Upcoming RPGs: Wasteland 2 Pillars of Eternity (not turn based but should be similar to BG series) Torment Tides of Numenera Lords of Xulima Telepath Tactics After Reset (currently running a Kickstarter)
Released PGs: Blackguards Shadowrun Returns (highly recommend the DLC/expansion as it is better than base game)
If you can stomach older graphics Spiderweb has several good series, Geneforge is my fav. Underrail is Fallout inspired and looking great so far.
While not turnbased, Gothic 1 & especially 2 are cult classics for a good reason.
I don't think anyone should have to sell you on PC gaming. If you just think about it from a logical perspective it basically sells itself. It can do anything a console can and more, but better and your range of gaming options is exponentially higher.
Also if Steam sales don't convince you, may the gaming gods have mercy on your digital soul, then nothing will.
Unless there is some console exclusive title that is a must have for you then you really can't go wrong with keeping your PC up to snuff for modern PC gaming.
Study shows haters are, in fact, going to hate. http://media.wix.com/ugd/e3eff4_4cac9b39aa2742f182d1cdd052d37107.pdf