If you are looking to buy a vintage device for ROM experimentation, these are the best candidates:

: You need a Device Dump (the actual ROM files from a phone) and the EKA2L1 app.

: Features a physical slide-out QWERTY keyboard and more RAM than the 5800, making it more capable for multitasking.

Are you planning to mod a , or are you looking to set up an emulator on your current phone?

Known for high speed and stability on the 5800 and 523x series. Daily use.

: Remove "bloatware" to free up RAM and CPU cycles, which is critical for older 434MHz or 600MHz processors.

Though more famous for Symbian^3 (N8/E7), version ports brought "Belle" style menus to S60v5. Modern UI look. Essential Devices for S60v5 Modding

: Port icons, fonts, and home screens from newer versions like Symbian Belle or even Nokia N8 designs.