Okay... so the reason you aren't really getting any answers about an interface is likely because it is a HUGE topic and it very much depends on your specific wants/needs. There are also so many different brands and options it can be overwhelming. So instead of making specific recommendations I'll just give you a breakdown of what is out there based on my past year of research. I will point out I am not a pro and still have a lot to learn so my opinions (when I offer them) aren't exactly expert.
So first let's look at the different ways interfaces connect to the computer and some of their benefits and disadvantages.
PCI: This is old school and PCI stuff is considered "Legacy" devices. You may see many new motherboards that say they have PCI slots (and they would) but quite often they are not able to handle intensive tasks such as audio or video production. The reason for this is the motherboard manufacturers decided to save money and likely space on the physical board by eliminating the chipsets which would normally handle the data going through the PCI slot. A board that has this chipset is said to have "Native" PCI support and a board that sends those tasks elsewhere on the board (I believe it usually gets sent to the PCIe chipset but I'm not sure) is called "Bridged" support. You can still get motherboards with Native PCI support but you have to look very closely at the specs. Sometimes they use terms like "PCI Sure" or "PCI Ready" but really you just want o make sure that it has a proper PCI chipset. Even then if the manufacturer used sub-par chips you could still run into problems. That said there is the fact that PCI is already considered a legacy device and will quite likely be completely phased out in the next few generations of motherboards so if you wanted to upgrade your system and use you PCI interface you would be out of luck. The point is you should avoid regular PCI interfaces.
PCIe (PCI express): These generally have native support and are definitely more modern. Most boards will have PCIe slots these days and I think it's usually done with Native support for the slot (not sure though). They are fast and can move a lot of data quickly. Again you'll want make sure your motherboard has a quality chipset to run it. PCIe will probably be around for a while but not forever and it may go the way of PCI in that it won't get as much attention as newer connection standards. You also have to physically install it and take up a slot you may want to use for other stuff. I personally wouldn't go this route either but it is a viable option.
Firewire: There are different kinds of firewire but I'm not too familiar with them all. I'm not sure if there is a specific standard that is preferred for audio interfaces. Firewire has been extremely popular for audio interfaces for many years because it can handle massive amounts of data at very high speeds and before USB 2.0 tech really came to maturity it was the best alternative to PCI interfaces. The only real problems with firewire is that again you need a quality firewire chipset for it to work well. In the past people would buy a specific firewire card for their computers but more and more motherboards started having firewire connectors right on the board. However again you NEED a quality chipset to handle the data or you might run into problems. It seems the general consensus is that if you want a quality firewire connection you should make sure your board has a Texas Instruments firewire chipset. I do not know how many different types of chipsets TI makes nor do I know which would be the best but if you decide on a firewire device it is something to look into. Also while firewire is still commonly used it is started to fall to the wayside in favor of USB connections. Firewire can handle much more data than USB but at the amounts of data USB 2.0 can handle these days it doesn't matter. From what I've read you would not be able to choke out a USB 2.0 connection no matter how many tracks or how much data you throw at it in an audio production setting... but I could be mistaken. So firewire is a good choice but you need to really keep an out out for the good chipsets and it may eventually become harder and harder to find a good motherboard to handle a firewire interface.
USB 1.0: There is no point getting a 1.0 device these days with all the quality/inexpensive 2.0 devices on the market so just ignore anything that says USB 1.0 or the other increments up to (but not including) 2.0. It is outdated and slow.
USB 2.0: Probably the simplest and most effective option. USB 2.0 is fast and powerful enough to handle pretty much any audio production task and it doesn't need any fancy chipsets or special considerations when purchasing computer parts. From what I understand it mostly comes down to the drivers so when looking at USB 2.0 devices do a bit of digging to see how up to date the drivers are and what people are saying about the drivers. For example I just purchased a Focusrite unit that many people had been having problems with until Focusrite fixed the driver for it. Now everyone seems quite happy with their products.
USB 3.0: Obviously this is high speed/high data transfer however there aren't many (if ANY) USB 3.0 interfaces. Some devices are able to use 3.0 connections but it is not recommended and you would only be getting 2.0 speeds out of it anyway. Will 3.0 take over at some point? I don't know and I'm not sure why it hasn't already but I'm sure there is a good reason for it. I still made sure I had plenty of 3.0 slots on my motherboard when I purchased it though just in case.
So I think that's pretty much all the types of device connections you'll be running into in your travels. I cannot stress to you enough that I am NOT an expert so this not definitive info. It is gathered from all over the internet and chatting with various engineer friends of mine. If I've left something out or made an error maybe some of the more knowledgable folks can chime in. Also please excuse any spelling errors or brainfarts.
Next I'll try to get a list of manufacturers together for you but I should get some of my own work done for now. I'll be back. Cheers.