"Start recording anytime just by pressing one button."
Map an application HW button to "Start recording" action along with activating "Use record button to launch Audio Recorder and start recording".
"Audio formats for every occassion."
Recording music or speech, with respect to quality, length, portability or power consumption:
MP3 — The most popular audio format ever. Widely supported by all platforms. Ideal trade off Between quality and hardware requirements. Ogg Vorbis — Alternative to MP3 with higher quality, but requires FASTER PDA. Speex — Outstanding speech compression ratio, but also needs fast device. WAV — Lossless quality, low hardware requirements, but huge memory consumption. RAF — Minimal hardware requirements, minimal energy consumption, compresstion ratio 4:1.