Question: The title of the question pretty much tells it all.

When using the java SDK provided by Crystal Reports to export a report as an Excel spread-sheet. Although the cells grow even now, only the first line is visible in the export XLS. 

In the Crystal Reports UI, this is achieved by setting the 'Grow' option from the Report Export options.

What parameter must be set so that the corresponding cell *visibly* grows to accomodate large/multi-line text?

Answer: 
LinqToSql is an ORM, so you are already using one. Taking LinqToSql out and replacing it with EntityFramework or NHibernate won't solve the problems you appear to be having right now.

Here are some things you should learn more about to help give you additional context:

* [AutoMapper](http://automapper.codeplex.com/)
* [Data Transfer Objects](http://en.wikipedia.org/wiki/Data_Transfer_Object) (DTOs)
* [Plain Old CLR Object](http://en.wikipedia.org/wiki/Plain_Old_CLR_Object) (POCO)
I've had a great time using Entity Framework 4.0 (+ the CTP). I think you'd have a much easier time dealing with an ORM like that. EF4 provides *everything* you need to interoperate with MSSQL from C#/.NET. You won't have to write a single line of SQL, and it has full support for LINQ (through ObjectQuery).