Thunderbolt has some inherent advantages over USB in that it ties directly to the PCIe lanes vs USB's "polling" system. It's not just total data rate. In a somewhat simplistic explanation, in USB, there is a buffer, and the system basically checks the buffer at intervals, dumps the buffer and moves on. If the processor is busy doing other things, it may take too long to check the USB flag, at which point you can get a buffer overrun and you can lose data which means a glitch in the audio.. The fix is to increase the buffer. That can cause latency (delay) in the sound (which can be calculated from the sample rate and the buffer size). Remember, it's a two way street, so it needs to process both up and down data. For moving a mouse or keyboard, it's not an issue. We're talking milliseconds, but in some cases, it can become significant. If you start getting over 10-20 ms in delay, some people notice a loss in response time.
Thunderbolt is able to tell the processor to process it's data, rather than waiting for the system to come back around the block. This means You can use smaller buffers and minimize the wait time between data transfers. The two technologies are now converging, so in a generation or so, there won't be any difference. Apple has been on Thunderbolt for a long time (and Firewire before that). The new Intel 690 and 790 chipsets support Thunderbolt. The key will be if the proper drivers are available.
It sounds like you're just starting out. If you are looking at a small Focusrite Scarlett interface, then you're talking USB. Thunderbolt interfaces tend to be more expensive, although that is changing. For USB interfaces, I've heard lots of people singing the praises of the Moto M4. Don't fall into the trap of getting a Solo or other single channel interface. The day will come that you'll want to record an acoustic guitar with 2 mics, and have someone sing. BINGO! You're out of inputs. 4 is the minimum I would consider, but I have 8 on my setup. Drummers can use up that whole thing.
With regards to the drives, I have a TB SSD and a 2TB Barracuda. It's served me fine for years. I've been upgrading systems to SSD and it is a huge improvement. A system that once took a minute and a half to boot up does so in about 10 seconds. No noise, no heat. I have two 4TB Seagate externals, and I can back up all my data, and clone the OS drive and STILL have room. I don't know how many songs you're planning but some of my bigger sessions are only 18GB total, and that's mix data, and several hours of multichannel audio. You can hold 2 or 3 hundred of those on a single back up drive for about $90.
The computer you are looking at should easily last 5-7 years. My system, a measly Lenovo H50 is 8 years old and still running fine. The demands of audio processing shouldn't increase dramatically. Where video has gone from 480i to 720p to 4K to 8k, audio won't be going much beyond the current max 384K. 192K and 24bit is more than sufficient for just about anything. The only increase I see in the near future would be going to full 32bit floating point. Current systems can handle that pretty easily.
I don't know much about Bandlab, but I would recommend you look at Reaper. It's cheap, free to try for 60 days, resource efficient and has great support. You can use as a basic recording setup, or get as complicated as you want. I looked at Ardour, but didn't like the workflow. I've used Cubase SE, and it was ok, but I really prefer Reaper.