No offense, but this is a specious argument that relies on some seriously erroneous assumptions... I propose that in the long run one can have fun
and be financially responsible. In fact, if you can manage to resist spending money on things that aren't really necessary the resulting financial security will allow you to do plenty of fun things and you won't wind up in the poor house in old age (or sooner...)
Consider this: $1000 of Apple stock purchased in 2004 is worth around $140,000 today. (Dates and amount approximate due to the fluctuations in the stock price, but the amount is in the ballpark...) $1000 is the difference in price between a base model 13" MBP and a 15" rMBP.
$140,000 can pay for a heck of a lot of "fun."
I realize that it can be difficult to resist the newest technological bauble dreamed up by the marketing and engineering geniuses at Apple. And that it can also be a drag to take the long view when you are just starting out in life. But there are important lessons to be learned from all those people who are currently suffering big time because they chose to mortgage their lives in the pursuit of bigger houses, more stuff and vacations paid by credit card and refinancing.
I prefer to learn from others' mistakes (not that I haven't made a few of my own over the years!) Digging-out of financial problems can take years to accomplish; a lot of people negatively affected by the housing and credit collapse will likely never be able to accomplish it in their remaining lifetimes.
Based on what Rockyroad55 has written previously, I think that his needs would be better served by a less expensive Mac and an external display. Doing research and writing on a large external display is going to be a lot easier and more pleasant than working on even an ultra high resolution 15" display for long periods of time.
Having done a LOT of work on 12", 13" and 15" Macs I would go with a 13" and an external monitor. (I actually used a 12" iBook as my primary computer for four years...

) I wouldn't want to be doing a lot of research and writing on any portable Mac screen, even a 15" ultra-high resolution display like the Retina. It is simply not a replacement for a good quality external display 24" or larger.
I was very interested in the 11" MBA but I discovered that its display was painful for me to use due to LED sensitivity. (There is a long thread about user problems with Apple's current LED displays on the Apple forum.) I didn't spend any time with the 13" MBA assuming that I would probably have the same problem with it.
And when I compared the 13" MBA to the base model 13" MBP the difference in cost and features led me to purchase the MBP. I got a new MBP for $909 and a soon to-be-discontinued high-end 24" NEC for $550 vs. the regular $899 cost. Sweet!
The base model 13" MBP has been available recently for $929 in the refurb store and $999 at Frys. (Unfortunately, the online store is currently out of stock and the sale ends 8/9/12.) There have even been some early 2011 13" MBP in the refurb store for only $800. That is a terrific deal and if another appears I'll be on it like a dog on a bone. (I already have that MBP and it meets all my needs and then some...)
Some university bookstores that sell Macs routinely snag large numbers of previous-generation new Macs and sell them to students and faculty at significant discounts. I have saved up to 50% on brand new iMacs and MacBook Pros going that route. So be sure to check with your college bookstore to see if this is an option for you.
I want to mention that on the DP Review forum a university computer tech recently reported that he sees a lot more MBAs coming in for repairs vs. MBPs due to normal wear-and-tear from typical college student use. His take on the situation is that the MBAs are not as robustly constructed as the MBPs.
I think that his perspective is worthy of consideration even though I expect some Macrumors denizens will see things differently. I value his input because he obviously sees a LOT more Macs than I ever will and he knows the hardware inside and out...
I just want to mention that in addition to hardware you are going to need software to run on whichever Mac you wind up with. Being in the research and writing biz myself I suggest demoing DEVONthink (
http://www.devontechnologies.com/products/devonthink/overview.html) and Scrivener (
http://www.literatureandlatte.com/scrivener.php). Both programs are reasonably priced (DT is usually discounted 30% on Black Friday if memory serves me...), very powerful and great time-savers. Be sure to check for student discounts.