OH ok, that makes perfect sense now.
I currently own a MBA, having come from a 15" 2007 MBP. The difference is night and day. I think the current 13" MBA is actually the best value MAC aside from the Mac Mini. The portability is impressive, the screen size doesn't feel like a compromise. That being said, I do not use it for heavy gaming, nor do I use it for heavy photo/video editing. I still do those things, just not on the extreme end.
Actually, when I got my Core i7 in early 2011, I thought of a MBA. However, at that time, the Sandy Bridge architecture had just been released, and the MBA was still stuck with Core 2 Duo processors (not even Nehalem). I found that an ULV Core 2 Duo processor would be too little for my needs and then I skipped it. There were no ultrabooks that could serve as alternatives at the time, and the unibody MBPs did not really appeal to me.
Then I found this Core i7 which had a lot of power, yet it was announced as having a decent battery life (5 hours due to NVIDIA Optimus technology, and which I later found to last much less than that) and not really heavy (5.6 lbs, which is about the same as the 15" MBP, although later I found out that the AC adapter, which I would always have to carry due to the poor battery life, was a heavy brick). And, still, it was a real bargain at about US$ 3,000 (well, you may find it expensive, but I would have to fork US$ 6,000 for a 15" MBP with similar specs at that time, and I was not willing to do that).
Looking back, it may have been some overkill. I don't play games and I don't do photo editing. I mainly browse the web and I am currently writing my PhD thesis. A large screen area is important for managing all the research papers and notes I have to, so I could take advantage of the 1920x1080 real estate. And the performance was welcomed, as the MacBook struggled to handle my library of over 1,000 PDFs.
Now, I guess I'm spoiled by the performance and the features of the i7.
I do not think the 1st gen 13" rMBP is worth the investment. In fact, I'm having a tough time comparing what next year's MBA and 13" rMBP could be without still favoring the MBA.
It's really a hard time. What could happen is the following (I'm not saying it will happen, nor that there is a strong chance it will happen, I'm just saying it may happen or not):
13" rMBP:
- may get a quad-core Haswell (depending on whether Intel will make mainstream quad-core processors for laptops or not);
- 256 GB SSD on the base model;
- better battery life;
- price may be reduced after the cMBP is discontinued.
13" MBA:
- may be redesigned and become even thinner and lighter with the adoption of new materials;
- may get a retina display;
- 8 GB DDR3 on the top-end model;
- Haswell ULV processor will allow a much better battery life;
- price may increase due to a possible redesign.
Apple may add some of these features to the 13" rMBP and MBA lines in 2013. It will probably not add all of them, but some of them will probably make their way into the 2013 line.
So, my advice, based on what you're saying, (great performance, thin & light, great keyboard & trackpad), would be to get a 15" rMBP. I would start saving now, so you can spend 3k next year on the Haswell refresh. That should be a computer that you can proudly use for 5 years. Coming from a 17" beast, you will really appreciate it!
I am actually more inclined towards the 13" rMBP than the 15" rMBP, actually, due to the portability. I feel, however, that the 15" rMBP is a much better value, with a quad-core processor, a dedicated video card, a larger SSD and a higher resolution display.
Anyway, the 13" rMBP is currently selling for US$ 3,500 and the 15" rMBP, for US$ 5,000. Although it is a lot of money, I'll certainly not last 5 years and I'll exchange it within the next 2-3 years, as I always do...