Giving my setup a facelift over the course of the year, could use some advice

[GordonZombie]

Alright, I've had the current build I have for about two years and lately I've noticed a couple of things that have caused me to consider a couple improvements. Current specs:

[B]CPU:[/B] i5 3570k OC'd at 4GHz
[B]Mobo:[/B] ASRock Z77 Pro3 Mobo
[B]Cooler:[/B] Coolermaster Hyper 212 Evo
[B]GPU:[/B] ASUS GTX 770 2GB
[B]RAM:[/B] 2x4 8GB Corsair Vengeance 1600Mhz
[B]PSU:[/B] Corsair RM750
[B]Case: [/B]Zalman Z9+ U3
[B]HDD 1:[/B] Western Digital 1TB
[B]HDD 2:[/B] Toshiba 2TB
[B]OS:[/B] Win7 Ultimate 64-bit
[B]Monitor:[/B] 1600x900 screen which I got off my stepdad's office setup for free. (Please don't lynch me).

Now, as for what I'm planning/not planning on or otherwise considering replacing:

[B]CPU: [/B]Not particularly interested in upgrading to an i7 as aside from the price they don't make that much of a difference and to my understanding the current generation i5s aren't that much of a performance improvement aside from power consumption(?).
[B]Mobo: [/B]Since about a year ago I've started regretting its purchase since it's not as effective when it comes to overclocking and there's been a little bit of damage to the plastic slide which helps to keep the GPU in place, nothing that stops me from using it but it means I've had to resort to ghetto methods to stop it from sagging as seen in [URL="http://i.imgur.com/XNQAjwB.jpg"]this outdated photo[/URL] taken during a much-needed tidy. My only gripe is that if I stick with my current CPU I'll have to get another 1155 and I dunno if that's worth it. Would prefer to keep to a budget of roughly £100 more or less for this.
[B]Cooler:[/B] Again, as long as I'm sticking with this CPU I'll probably hang onto this until I decide I want to try a watercooling setup.
[B]GPU:[/B] I'm not sure. I've only had this since October '13 but I've not had the performance I'd expect with certain titles and judging by the next few years' upcoming titles, it's not looking good. Plus, I'm interested in what Nvidia might be releasing later on this year.
[B]RAM: [/B]I'll probably throw in another 8GB at some point, no need for now though.
[B]PSU[/B]: Don't think I'll need to replace this for a long time unless I decide to fit a set of SLI'd Titan Zs in my case.
[B]Case:[/B] Definitely getting replaced. There's quite a few annoying design flaws such as the clips at the back to remove the top panel being located right in the corner where it's impossible to access without scraping the corner of my mobo's I/O and the front panel has the double issue of coming loose way too easily and the plates for the disc drives being knocked out by the most insignificant amount of pressure. At any rate, I don't want to be spending too much on my new case so a decent midi tower (I prefer windowed cases) within a budget about £80-90 should be decent enough.
[B]HDD 1:[/B] I'll be hanging onto this for the time being.
[B]HDD 2:[/B] Same as above.
[B]OS:[/B] I'll probably stick with Win7 for a while after 10's release until they give it a decent polish. 8 seems too different for my liking.
[B]Monitor:[/B] Probably the first thing I'm going to replace. I'm not after anything too fancy though, just a decent 1920x1080 display for a budget within the field of £90-120 give or take.

So yeah, I'd like some advice on the matter and whether or not some of it's worth replacing. As well as suggestions for the stuff I do want to replace.

[Levelog]

Alright, here's all what I'd recommend. For the motherboard, the only one I really saw on here that was worth the money is the Asrock Extreme4. There's a big difference in overclockablility from the Pro3 to the Extreme4, as you're changing from the absolute budget end to the midrange. For a case, I put in the NZXT H440. Some of the other color schemes are a bit cheaper, up to you. It's a fantastic case, and quiet as hell. Another option in that price range is the Fractal Design R4. For a monitor I basically put in the cheapest 1920x1080 IPS display.

[url=http://uk.pcpartpicker.com/p/LZPF3C]PCPartPicker part list[/url] / [url=http://uk.pcpartpicker.com/p/LZPF3C/by_merchant/]Price breakdown by merchant[/url]

[b]Motherboard:[/b] [url=http://uk.pcpartpicker.com/part/asrock-motherboard-z77extreme4]ASRock Z77 Extreme4 ATX LGA1155 Motherboard[/url] (£95.64 @ CCL Computers)
[b]Case:[/b] [url=http://uk.pcpartpicker.com/part/nzxt-case-cah440ww1]NZXT H440 (White/Black) ATX Mid Tower Case[/url] (£89.99 @ Amazon UK)
[b]Monitor:[/b] [url=http://uk.pcpartpicker.com/part/lg-monitor-22mp55hqp]LG 22MP55HQ-P 60Hz 22.0" Monitor[/url] (£101.09 @ CCL Computers)
[b]Total:[/b] £286.72
[i]Prices include shipping, taxes, and discounts when available[/i]
[i]Generated by PCPartPicker 2015-01-14 00:01 GMT+0000[/i]

[editline]13th January 2015[/editline]

Go with the ASUS board you linked in quick questions, actually.

[GordonZombie]

I'm a little skeptical on the H440, it's going to be a little awkward for me without an internal disc drive but otherwise I'll admit I really do like the look of it.