We describe the VLSI implementation of MIMO detectors that exhibit close-to optimum error-rate performance, but still achieve high throughput at low silicon area. In particular, algorithms and VLSI architectures for sphere decoding (SD) and K-best detection are considered, and the corresponding trade-offs between uncoded error-rate performance, silicon area, and throughput are explored. We show that SD with a per-block run-time constraint is best suited for practical implementations.