Just went through this same exercise for my daughter. Basically, I asked myself what's likely to break, and how to construct this system to keep from getting a frantic "Dad! My computer just beeps and has one line that says 'OS NOT FOUND. DISK @ IDE0,0 NOT RESPONDING' over and over! I have a 25-page paper on there that's due tomorrow! HELP!!!" call. No amount of "Honey, that's why the tell you to print your work out a day or two ahead." is going to fix that.In her system, I opted for a LeadTek TV2000 XP deluxe TV/FM card in order to forgo a TV, stereo, and DVD player. You may want to consider the same as these dorm rooms are incredibly small. Also, since she's going to be sleeping, eating, living and perhaps even studying just feet away from this thing, overall noise was a consideration.
In my experience, the top things that fail are fans (CPU, case, and power supply), optical drives, and hard drives - more or less in that order. I didn't see any additional fans in your list, but I would consider adding the rear 80 mm fan, plus buying a spare. I would consider getting two quiet fans and using the one that comes with the case as the spare. A spare CPU cooling fan is a good idea too. I've had a number of those fail - and you really, really don't want those to be down long. (I'll mention Motherboard Monitor here as a good thing to have to watch those fan speeds.)
I've had a few optical drives fail for different reasons such as they just stopped reading anything (laser died or something) and in one case, the tray loading mechanism permanently jammed in the open position. For my daughter, I bought a pair of matching combination DVD-ROM/CD-RW drives at NewEgg for about $70 each. Either drive could fail and she could still read DVDs and read/write CD-Rs and CD-RWs. What you have specified is probably just fine though.
For disk "protection," I'm using a motherboard with on-board RAID support and using RAID-1 (mirroring) with two identical drives so that each drive is a copy of the other. It can still run with one drive if one fails, which gives me some time to pick up another drive and get it shipped.
I also bought a pair of DDR modules so that one could fail and she could get by for a while on just the other. I've only once had memory fail after it's been working for a while. I've gotten a couple of sticks that were DOA on arrival or died shortly thereafter though. I got this system ahead of time to have a decent burn-in period.
I went single point of failure on the motherboard (What choice is there really?), CPU, floppy (not even sure she needs one), TV card, power supply and video card. (The LAN and sound are built-in.) I briefly considered a dual-CPU motherboard, but I've yet to loose a processor, even when the CPU fan quits. Those fans tend to get pretty noisy before they fail, so I've always had enough time to get a new one before it totally fails. My thinking on the other parts are the following: If the motherboard fails, she's out of luck, but I couldn't see buying a spare. I've never lost a motherboard yet in any of the dozen or so computers I've had over the 18 years. I bought a quality motherboard and have faith in it. If the CPU fails, she's toast, but I've never had that happen. It does happen though. The disk drives on the Sonata are easily removable, so she could get to the data using someone else's computer in a crunch in the case of a motherboard or CPU failure. If the floppy fails, I'm not sure she'd notice and the CD-RWs will still be there. TV card fails: "Tough luck honey. We'll get you one during your next break. Study more." Power supply: I really did think about picking up another one. I've only lost one power supply, but I've replace the fans in several. The 380W Antec power supply comes from a company with a good reputation, and I've had great experiences with them. I've no experience with Enlight's power supplies. If it's not Enermax or Antec, I'd be a bit hesitant. That power supply's seems bit light on the all three rails for a 300W p/s, but it's probably OK for what you're assembling.
If you are thinking of getting a quiet system, I highly recommend the Antec case. It's roomy and very, very quiet. Even with the second (stealth) 120 mm fan, I can barely hear it. I got the Antec Sonata case and put a second PC Toys Stealth 120 mm fan in in plus bought a spare. (I got those and the round IDE and floppy cables from coolerguys.com. NewEgg's shipping is steep on those items.) Cooling is a concern because most of the dorm rooms are not air conditioned and they are "warm" in the early fall and late spring. The round cables help not block off the airflow. In this particular case, they are also easier to route around.
I got her an 17" LCD monitor. 1280x1024 at 14 lbs. My 19" monitor has the same resolution at 60 lbs. What would you like to lug up and down the stairs?
If the girl your building this for has her college ID, she can get the upgrade version of Windows XP from NewEgg for $88 if you have something to upgrade from. I'm not sure how (or even if) NewEgg verifies she's a student.
-cap