I am thinking of upgrading my PC with a new processor because I want to play the latest games with perfect 60 FPS on Utlra settings.

Playing Total War: Warhammer when things get chaotic and on ultra hampers my framerate.

I know the latest Intel Processor is an i7 right now but there are so many variations I don't know where to start.

There isn't any good processor on the market now. All of them suffer from the meltdown and spectre issues, so until the next generation of processors come to the market, I wouldn't be buying any, Intel or AMD.
There may be a couple of processors that don't suffer from either flaw, but I'm not sure which ones they are or how good their performance is.

Well I had my current processor (an Intel Core i5 4670) built into my PC when I first bought it for years now and so far it hasn't been melted and such.

How long do these Processors last usually?

All of Intel, AMD, and ARM processors are affected by Spectre, but
AMD denied that their products are affected by Meltdown.

Almost all Intel CPUs on the market now are affected by Meltdown.

ARM chips that are affected by Meltdown:
https://developer.arm.com/support/security-update

Oh so we aren't taking about Processors litirally melting?!

So what is this Meltdown you guys are talking about?

A processor that is not overvolted and properly cooled can last thirty years.

A core i5-4670 is still very good for gaming and if it is slow either the cooling has problems:
--TIM paste gone bad, cooler not properly in place, too much dust, damage due to too high voltage, cooler fan not fully working and last and least likely you have a super rare bad processor but they carry long guarantees so might be Intel still would fix or replace it.
or:
--The problem lies elsewhere.

'Meltdown' is a security bug in the processor. A software fix slows down the computing speed quite a bit. There will come new processors with the bug fixed in the hardware late this year or next year.

Even the ones who came up with these terms, can't give you the right picture of what is about. Not to mention the interpretation of different people from east to west with or without knowledge about it. It's not the end, it's just the beginning of the end.

Cheers.

Both are hardware design flaw, security bugs that are hardly to detect.
Major Operating Systems have fixed the Meltdown bug, but users have to upgrade their OS.
Spectre is not a single bug, so it is not possible to fix it with simple solutions.

So....no one is gonna recommend me a new processor?

Ok if you really need that CPU upgrade, you can go for i5 8400 and upgrade around it with other components.

Since you absolutely want a suggestion, the best consumer gaming Intel processor right now is the i7 8700K.

You didn't tell us at what resolution you are going to play.

Not really as it would not be more than a little faster than your current one but if you are rich and want Intel, decide between an 8600K and 8700K depending on what games you play but the upcoming fixed processors might trounce these by 10-25%.

Maybe you only need to remove dust? Reinstall Windows? Add RAM? Better graphics card?

Go with any of the above suggestions. Just be aware that you'd be buying hardware with a known flaw. If you need to buy it now, do so, but if you don't need it, but just want an upgrade, wait.

I am not sure if what I read is right, but it eas said that to solve the spectre and meltdown issues at hardware level, they need a new design and this may take 2-3 years