Aspectrum is (another) Spectrum Emulator.
It's programing completly in C, so its multiplatform, actually for Windows, Linux and MsDos.
It's the first emulator to support the Gunstick Light Gun, and can emulate the spanish flavours of Sinclair Models.
Can emulate 16K, 48K, 128K, support save and load of .SP, .SNA, .Z80 snapshots, and .TAP, .TZX Tape files with flash load.
Also have a Z80 debugger.