I run a number of DOS based games on old computers and this is my experince.

DOSBox is great but it can make some games chug depending on your hardware, it may slow down depending on what is going on in the background and certain keys may bring up windows programs.

Personally I run everything on their own computers for DOS.

Get a machine that does have PS2 ports for mouse and keyboard, for most DOS games the low hundred Mhz is fine.
Use a CRT monitor.
If the game needs pure dos then I suggest either MS-DOS 6.22 or FreedDOS, both have memory options to get the most memory from the system. Else Windows 98SE is a good alternative.
PCI soundcards can be easier to set up, BUT only if they have DOS drivers the early Creative Soundblaster PCI cards tend to have these but later ones do not and may not work on DOS at all. An ISA soundcard may need some setting up but it is not too hard.
As recommended use cutemouse for the mouse driver it is tiny.
Most CD-ROM can support DOS easily, although drivers may be harder to find but Windows will have most of them. Alternatively find cracked or NOCD patches for games.
If using DOS then you'll get very used to editing the CONFIG.SYS and AUTOEXEC.BAT files and remembering switch settings for HIMEM.SYS
However once you have everything perfect then it does feel more nostalgic and better then playing the game on a moderrn PC with it's soulless LCD display.