Basic MIDI KEYBOARD question

I've been using Sonar for several years, and I've used MIDI for even longer.  But I have a question for a friend of mine who's looking to get started recording MIDI in Sonar.
 
I run my own MIDI keyboard into my EMU 1820M DI interface via MIDI cable, so my question is this.
 
 My friend is just looking to record MIDI tracks with a MIDI keyboard via USB cable.
 He's will be using Dim Pro / Rapture and mixing via headphones (for awhile, while he is getting started).
 
Does he need a DI box, or can he just go into his computer's USB 2.0 port? 
And will his on-board sound card be sufficient until he gets set up with speakers or needs to expand beyond MIDI only?
 
I'm not able to answer his questions since I bought my system all configured and I am hooked up to my EMU.   I don't think initially he would be creating more the a few tracks and hopefully importing some of my tracks to add some keyboard to.  He is a very good keyboardist, but he's new to home recording.  Once he knows what he needs he will buy a MIDI keyboard and Sonar, but I'm trying to find out what he needs at a minimum to just get started (As we all know once you're hooked you will buy all the other stuff!)  He has a farily new computer but with a standard sound card configuration.
 
Thanks for any information or tips.
 
Daryl

Actual recording of MIDI is not a problem because the data by itself is not that much for any current PC or laptop.

The problem is the making of the sound, which means converting the MIDI signal to audio. That means the need of a MIDI sound module, or MIDI player.

For that, ASIO drivers are the answer. Since most built-in soundcards don't have ASIO drivers, they do have a latency problem.

HOWEVER, if you have an external HARDWARE MIDI sound module, then you set that to make the sound of the MIDI data, and there should be no latency. See? The built-in sound card is not working at all to make sound.

If not, then a soundcard with ASIO drivers can be added to the PC or to the laptop, OR an external USB or Firewire audio interface, which essentially has its own sound card built in.

By the way, some keyboards with built-in sounds can serve also as an external MIDI sound player.

But again, if you go external MIDI sound player, the qualities of the sound may not match the newer software-based sound sources. That's why ASIO supporting interfaces are pretty much the answer. Best when the ASIO drivers are multi-client.

Is your friend working with a PC, or a laptop?
If it's a PC, I might suggest investing in an EMU0404(PCI version), or M-Audio2496 right off the bat. Neither of these has built-in preamps, but they do have decent converters, and are capable of acceptably low latency. At roughly $100, maybe less, they are very good start-up cards.
The 0404 uses the Patchmix GUI, which some find a bit daunting, but you can help him with that. The 2496 is easier to set up, but not quite as flexible.
He can add a small mixer later if needed, for preamps.
For real-time recording of soft synths, I find latency of 10ms or greater very annoying. I suspect your friend would as well.
Since he will be using Dim Pro/Rapture (or any soft synth for that matter), I would make the minor investment, and spare him the frustration of trying to deal with th built-in sound card.
The USB input itself is fine, and I have been recording this way for a few years, using an Edirol PCR-M50 via USB.
With soft synths, the sound card (and CPU) is the kicker.

I also like Patchmix, but it seems to confuse a lot of folks.
The 0404(PCI) uses Patchmix, but the USB version does not.
I really like my 0404, and as a one man show, it is plenty capable of what I need from it.