I use a few different ones. I'd recommend certain products based on whether you want to spend $$.
For most of my forecasting at work, I have an account with Pivotal Weather ($9.99/mo). It has about 95% of the things I need - global & mesoscale models along with short terms. That group has also been adding more ensemble products, which has been great.
I make some weather content still at home when I'm not working. For that, I use GREarth ($15/mo.), which is now split into two products - GREarth & GRModels. Not great # of model products available, but the nowcasting with GRE is great and I love being able to customize the data representation in GRModels.
Still use Bufkit (free) for a lot of forecasting sounding products but Pivotal Weather also includes that with their models which is nice.
Some other great free products are Tropical Tidbits, College of Dupage, Polar WX & Weather Nerds - I've use all of these in some form from time to time.
Weather Models (I believe it's $15/mo) and Weatherbell ($25/mo.) are also nice. I'm just not as big of a fan of their interfaces. Allisonhouse also provides a model map service but it was a bit clunky in my personal experience. I do use their data feeds for use and have never not been satisfied.
I do miss Simuawips.