I am a casual BIB user. My present laptop is  of the Windows 7 vintage. 
The processor is an I3 350M, with 4 gb ram.  I use an external sound card because the sound card on the laptop isnt  working properly.  The external sound card is probably a good thing in any case. Im plugged into my digital piano Yamaha CVP 709.  I run BIB  from the external hard drive.
Im thinking it is time to upgrade the laptop as it is likely not up to scratch and W7 will be unsupported next month.  I ve just upgraded to BIB 2020 (although havent opened the box yet). 

What suggestions might you more experienced than I have with respect to a new laptop?

Brian

Brian,
Depending on your budget, I can tell you that I've had very good performance with a Lenovo "Flex" series laptop, Costco, BestBuy and probably newegg.com can offer good deals and generally BestBuy will price match.   If you get at least an i7 Intel processor of the 8th generation with 16GB of RAM and a 512GB solid state boot drive, your external BIAB should work great.   Connect to your CVP with USB and you're good for lots of pleasant performance.

If budget is a big issue, then even an Intel i7 of the 7th generation will do nicely.  Don't scrimp on RAM or size of the SSD boot drive.

The Flex series that I have is a 2-in-1 (laptop that can be a touch screen tablet).   I also run MobileSheets on it so if I want to play along, I have my scores (in PDF) handy.   MobileSheets is very inexpensive, get it from the Microsoft Store/online....about $20 as I recall.

HTH
Dave