Alarms can cause all sorts of problems in addition to drained batteries and unless very sleathily fitted are easy to disable.
I've never had a bike stolen (touch wood) and used to live in Brighton & London in UK, where vehicle theft is rife.
I still have the biggest Abus Granite Lock I could buy 20 years ago and their largest padlock. They cost around $500 back then so they took them off the market as I guess they'd be too expensive today... Weight is around 20kg.
I also use a decent bike cover on each bike and keep the steering locks on.
These days where we live (in the countryside) there's no problem with theft, but they'd have to make a helluva racket with a grinder for around 10 minutes to get through the chain locking the VFR & SP2 together - and we have a dog who will bark with any disturbance at night. In the next couple of years the bikes will live in a very secure workshop too.
Not into disc locks myself as they'll damage fenders, marr expensive calipers, etc. if forgotten - and you do forget them...
When I ride the bike somewhere, I know where it'll be safe and I'm never far away anyways. Plus (thankfully) Japan is a relatively safe country where theft isn't such a problem - although that doesn't mean it doesn't exist...
Euro RC51 SP2: HRC WSB Ti Hi-Level, T1 Airbox & Snorkel, PCIII, Dymag CA5 Carbon Wheels, Ti64 Spindles (F, R & Swing Arm), Mori Link, Maxton GP7 Shock & Ohlins 832 Forks, Brembo GP Calipers & SBK narrow track (F), Braketech Disc (R), Brembo billet Underslung x 2 Brembo RCS, Tyga Triple, 7075 Stem, Probolt Titanium all over, Babyface rearsets, MR Complete Carbon Lineup, Custom Undertail & CBR 1000 LED, Watsen LED Indicators, Harris Brace, Giles clip-ons, Corbin seat, etc. 2013 BOTY.