Continuing issues with iMac i7

Question

I bought an iMac i7 27" just under a year ago.
Within a month of ownership the cooling fans powered up to 100% and refused to switch off - it was like working next to a couple of hairdryers. (apple support said it was cooling like that because I was watching HD youtube videos....)
I drove to the Apple store about 30mins away and, after a week or so, Apple fixed it.
Then, after a few months when it felt like it was getting a lot hotter than I'd expect the HDD started reporting errors.
I drove 30mins to the Apple store, they confirmed it was failing and after a week or so swapped out the hdd.
Then after another few months of it getting seriously hot the display started freezing with glithes appearing on the screen. Display was unresponsive although the system appeared to be still working.
I drove 30mins to the Apple store two weeks ago, Apple confirmed the graphics card had errors, I epressed my concern about the heat and that it had cooked the system leading to a shortened lifespan. Apple swapped out the gfx card and logicboard.
I've just returned from the Apple store to find that the display port adapter doesn't line up with the casing and I can't plugin my wacom cintiq.
I've lost complete faith in this unit, something else is no doubt going to fail shortly, I don't want to tolerate the condescending platitudes of the phone support  and if I have to drive back to the Apple store I'm likely to have a good go at throwing it through their window.
/rant

Answer 1

Thanks for the reply, I lost this post and wanted to update it. 
I didn't take out any additional protection plan purely because I've rarely had any failures with computer hardware (been putting together systems since the intel 486 and have a IBM thinkpad over 15 yrs old that's working perfectly). Wasn't long ago that I gave away a perfectly working SE30.
Anyway, update is that I phoned the store who offered to look at it right away if I bought it back. I wasn't in the mood for another drive back to the store - in total I've spent about 3 full days calling support, dropping off and picking up. The store brought it to the store managers attention and also put me through to support advisor and then onto senior tech - they've offered a replacement unit which is good news as I fully believed that this one would fail again and again. Personally I'd rather have just had a working machine from the start but these things happen - considering this was a cascade failure due to over heating issues it would have been more efficient to have done this or a complete repair and soak test from the start. But hey, it's all being sorted and Apple are back in my good books. Thanks for the reply!