CRM Helpdesk Software - What would YOU recommend?

Hi Experts,

I run a small technical support business for companies and schools in my area.  I have spent a substantial amount of time looking for a suitable CRM/Helpdesk Solution without success.

The criteria for the solution I'm seeking are as follows:

1. Web-based : SaaS with Smartphone / Tablet Integration as I'm always on the move

2. Helpdesk / Ticketing  with escalation and standard features. Email piping,

3. Calendar integration : The application can either have its own calendar or Google calendar integration. Should be able to turn tickets into appointments

4. CRM

5. Email marketing option to stay in touch with customers and keep them up-to-date.

I have looked at:

1. Autotask: Too sophisticated and expensive for my needs.
2. Kayako: Lovely interface, fine helpdesk but no calendar integration!

Many others have add-on modules that quckly raise the costs.  This is a small business so perhaps there is someone out there in a similar position who may have the answer.  I realise that there is no "perfect" solution but I would welcome any tips you might have,