You are talking about the connection between your drum kit and your computer, but mention delay and latency. Delay and latency do not occur between your drum kit and your computer, but between your computer and your headphones or speakers. I will do a quick drawing and then start at the beginning, up to the end

Drum kit => MIDI to USB => Computer (DAW) => Sound interface => Headphones or speakers

Your drum kit creates its own sounds, but can also be used as a MIDI controller. A MIDI controller does not create any sounds, but sends MIDI signals to another device. MIDI signals are simply commands to another device to do something. Pressing a key on a MIDI controller might play a note on the other device, raise the volume, control LFO, et cetera. A MIDI signal is a MIDI signal, no matter how it is sent from your drum kit to your computer, so it might be the easiest for you to use a MIDI to USB cable, but read on to the sound interface for more on this.

Once the MIDI signal reaches your computer, your Digital Audio Workstation (DAW) will need to process the commands. Your DAW is the software which you use. If you twist a knob, move a slider, play a note, then your DAW will need to transform this into sounds. These sounds are played by your sound interface, it is what you hear through your headphones or speakers and this is where the delay and latency occurs.

Sound cards which are onboard (soldered onto the motherboard of your computer or laptop) are not intended for creating music. Separate sound cards, for example by Creative, are also not intended for creating music although they will perform somewhat better than onboard sound cards. There are two problems with these kinds of sound cards: 1. delay and latency, 2. the sound they produce.

To get rid of the latency, you will need to use a proper sound interface which is intended for music creation and which offers close to zero latency. Brands such as Edirol, M-Audio, Novation, Tascam and EMU for example all produce proper sound interfaces. Most will connect via USB, some via FireWire. I personally prefer USB over FireWire since every computer will have an USB input, but not every computer will have a FireWire input. Being external, you can use such a sound interface with your normal computer, but can take it with you together with a laptop to if you please. Most proper sound interfaces will have MIDI inputs to connect your equipment to, so you could use a MIDI cable to connect your drum kit to your sound interface. I prefer to have every piece of equipment hooked up to my computer by itself, so every device gets connected to my computer via its own USB connector.

If you would not change your sound card, you might get used to the latency and you might learn how to deal with it, but there is one thing which you will never be able to get used to and that it the sound that a normal sound card produces. Normal sound cards "color" the sound. They are intended to "make music sound nice", which is something you do not want. I cannot stress this enough: you do not want your sound card (or headphones or speakers, more on that later) to color your sound! You want to hear your music exactly the way it sounds. If your sound card colors the sound, when you play your music somewhere else, you will notice that there is too much bass in your recording for example, or to less reverb, the beats cannot be heard or have too much punch to them, et cetera. You want to hear your music "as is" so that it will sound best everywhere. Proper sound interfaces do not color the sound. They play it back to you the way the sound is. They are not intended to make it sound better like normal sound cards do.

A proper sound interface is worthless if you have headphones or speakers which color the sound as well and all normal headphones and speakers do. You will need to purchase monitor speakers, or monitors for short (not to be confused with your computer screen which can be referred to as a monitor as well). Monitors are speakers which do not color your sound like normal speakers. Every monitor will sound different as speakers are difficult to produce so that they will not color the sound. One monitor might play the highs harder than another monitor for example, even though both are considered monitors. You cannot purchase monitors without hearing them. Go to a music store and listen to various monitors. I always advise KRK Rokit Powered 5 Generation 2 monitors, or KRK RP5 G2 for short. KRK offers great value for money and their RP5 G2 is a perfect size for most home studios. But do not take my word for it, but go and listen to some monitors.

Hopefully this has explained you a bit how everything works. If you have more questions, feel free to contact me. There are not many (computer) musicians on Yahoo! Answers. Good luck with your music!