Either way, it is hard to go wrong. It’s your choice really, a little better power consumption/heat dissipation requirements vs. a little better performance. Unless you are doing something processor intensive (commercial skip analysis, software-based video encoding), there’s not much use to the slight improvement in performance of the i3-2120 for HTPC applications. The i3-2100t is better suited to smaller and thinner chassis as well as quieter system.
