I'll second the Sheraton Grande if you're looking for an executive lounge. The upcharge to the executive floor usually isn't huge and you get some nice benefits. Breakfast doesn't have as much variety as the restaurant downstairs but it's quieter. It may include a laundry allowance too.

I also like Les Suites Taipei (Ching-cheng). They don't have an executive lounge nor an on-site restaurant (breakfast only) but they have some very nice common areas and an evening reception for all guests.